Fürstbischof
Chieftain
- Joined
- Jul 20, 2018
- Messages
- 90
Gameplay concept for WTP
[Eras should not play a prominent role re "research". Since eras are ATM only used in the background to determine the lengths of game phases they should be kept invisible. We might rely on eras to invisibly split the FF screens and thus introduce a steeper cost increase for the first FF in the next era. If we group FFs according to their time of activity and distribute each of them to their era we can even think about randomising the order in which they become available thus making perfect plans less valid. Expanding on that thought and taking into account that there are far more interesting alternative FFs not included in the mod we should think about having a surplus of FFs for each era from which the actual FFs are picked.]
[IMHO a tech tree as known from CIV should be avoided at all costs since it doesn't really fit to the time frame. There should be no research points and no active research by the player. We don't need another mini-game as a time sink. Turns in mid-to-late game take already too long.]
In the "tech" tree I envision for WTP, "research" will be happening automatically but often influenced by your own ingame decisions. Yep, you simply play the game and inventions, innovations and discoveries will happen while you play. The location of your home country, your colonies, the extent of your exploration, your colonial production and also the number of your battles fought in New World terrain will influence how many "techs" you "research". There will also be "techs" which will be made public beyond a certain date, i.e. you've heard about it in Europe. Buildings, units, improvements etc. will be unlocked by "techs" step-by-step.
inventions, innovations and discoveries
Inventions will happen circa at the historical date, maybe slightly randomised. Innovations, i.e. improved production processes, will happen at best at the historical date, but will be sort of randomised depending on the crops and manufactured goods produced by your colonies. Discoveries are the result of "your" voyages of discovery. Discoveries can happen anytime once the requirements are fulfilled. Knowledge of New World crops and terrain bonuses are 'gained=learned' depending upon how you play the game.
number of "tech" screens
I'm not sure how many "tech" screens are actually needed. Main themes are exploration (improved sailing, advanced ships), military (army/naval, improved units) and economy (unknown crops, production processes, advanced buildings, better improvements). As you see I'm favouring 3 screens right now, but that depends upon the layout of "techs". The "techs" on each screen are not dedicated to a specific era but are grouped with similar "techs". I don't know if we want to name the screens, but the names used for the eras don't fit well.
screen #1 : Exploration
The first screen is dedicated to Exploration and will have a full screen historical map showing the Americas in addition to parts of Western Europe and a good part of the African coast. The Atlantic is featured prominently and has blank fields where we today locate the prevailing winds (https://en.wikipedia.org/wiki/Trade_winds), known as westerlies and trade winds, and ocean currents (https://en.wikipedia.org/wiki/Ocean_current) of the Atlantic Ocean and the Pacific Ocean. While playing you will discover these and thus gain ingame advantages, like e.g. reduced travel times to Europe, Africa or the Western coast of America, or alternatively opening new destinations, i.e. the African slave ports.
Technically the game map is split into 6 'blocks' on each side of the American continent. We usually see that only when we try to freely choose a region in the Americas instead of a known colony for our departing ships. The game can track the regions of which we have gained enough knowledge so that we can sail directly there. The same mechanism would be used to determine which of the prevailing winds and ocean currents you might have discovered. In addition are several Atlantic crossings to/from a specific region necessary to clearly identify the prevailing winds and especially the ocean currents in that zone of the Atlantic. The discovery of ocean currents does take way longer than that of prevailing winds, i.e. requires many more Atlantic crossings, to confirm the existance of an ocean current. Their discovery should be reserved to the mid-to-late game. Keeping track of this will be done completely in the background. Discoveries will be made once you've passed the thresholds. Over time your ships will enjoy reduced travel times to all of the 12 coastal regions of the American Coast, but only if you actively explored each region. Travel times should be changed to reflect the actual distance from your home country to each region. South America and the Western coast of America will then always be the farthest away. [Sadly, sailing ships in the mod will then take far longer for their journeys than IRL. I don't know of an easy way to circumvent this.]
Such knowledge can otherwise only be gained by recruiting a founding father who is renowned for his voyages of discovery. The knowledge of these FFs is not mutually exclusive, e.g. Magellan and Drake. [Columbus had some knowledge of several of them, thus giving Spain a head start towards the Caribbean. Portugal had already made a bunch of southward travels along the African coast and thus a head start towards South America. English and French fishermen were fishing on the Grand Banks thus giving their countries a head start towards North America. We can ofc do without this previous knowledge since we've randomised starting locations.]
discoveries & new naval units
Once a certain number of prevailing winds or ocean currents are confirmed these in addition to the accumulated sailing experience, simply counting ocean plots travelled in the Americas and also the number of Atlantic crossings, can give you access to new hull forms, i.e. more roomier ships, like e.g. the galleon. Being ahead in exploration might lead to being the inventor of this new ship design. Staggered by their own achievements the other players will also discover this new design, or, if very backwards, they'll learn from this invention from other European sources, e.g. your home country, once a certain cool down phase has been passed (5 years?). Knowledge in your home country goes along with buyable in Europe. Nonetheless we might want to introduce a trickle-down delay to hinder the immediate usage of newly gained "techs" by your own shipyards. [Regarding naval units actually two trickle-down delays are required before the European colonies can start to apprehend the new "tech".]
It took a long way from the original lateen-rigged caravel to the three-masted fully-rigged ship of the 18th century so that a part of the screen should be reserved for "techs" dedicated to sails, masts and hulls. The development of cannons played an important role in the development of warships, but also highly influenced the capabilities of field and siege artillery. Not only the 18th century ships but actually all ships should require the passing of their historical build date before they can be bought (or build) to restrict them to the appropriate historical phase of the game. Due to sharp reductions in length of game turns, i.e. by going from yearly to quarterly turns, we should also add minimum build times (in months/years) for naval units to keep these realistic. The acquisition of ships in Europe should no longer be instant, but instead adhere to historical build times. To compensate we might alleviate the old CIV rule "only 1 build per city" by allowing smaller units to be build in batches, i.e. introducing building in parallel.
In total, the number of available naval units at any time during the game will be way less than now, but each ship will have its place (role/function) in the game, so no longer a good part of the ships can be safely ignored by players by simply picking advanced late-game ships ... way ahead of time. The most relevant UnitCombatTypes will be (in modern terms) flagship - battleship - cruiser - coast guard and large merchantman - medium merchantman - colonial "coastal" merchantman. This is the role/function a ship has to fit in.
inventions happen at their historical dates
Some inventions might be used as chokepoints, i.e. these will be triggered at their historical dates and thus can not be influenced by player actions. A prime example would be the implementation of the idea to have several spars tied together, thus creating the tops, instead of having one large pole as a mast. The same can be said about the development of naval tactics which is based on European combat experience. Naval tactics relate to the operational manoeuvring of formations which were interwoven with the evolution of cannons and ship designs. Ships with (same caliber) cannons arranged in full battery decks were the requirement for the firing of broadsides which led to the introduction of line-of-battle tactics. Your king will simply inform you once the Royal Navy has adopted new tactics. [ancient Halfmoon formation/galley tactics -> "Skirmish/Melee formation" -> Line Tactics (1670s) plus maybe the restrictive English Battle Instructions (~1750)] Naval tactics are important for the development of new (battleship) designs but have less influence on playing in the Americas since we have no true squadron warfare.
Naval inventions will usually be required for the introduction of improved naval designs and thus influencing their superior stats. Rarely the effects of inventions, like e.g. the refracting telescope of Hans Lipperhey in 1608, will be applied [maybe after having entered one of your colonial ports] to all existing ships. A rather different example would be the carronade, which was introduced by the Royal Navy in the 1770s. That is very late in the game and keeping in mind that it was a very powerful 'secret weapon' that it should only be available to ships of His Majesty - unless captured by you. Since the French took 20 years to copy the design your own ships won't be able to benefit from this invention.
re 'promotions'
You might seem to miss the word 'promotions' in my concept. They're almost gone. Several of them offered bonuses which were not even closely combat-related while in general the 'frequent' replacement of outdated units with more modern units leaves no place for a sub-system which heavily relies on accumulating xp, especially if it can flourish only in (rare) times of war. Having highly experienced, iconic units is a game concept which might fit for a WW2 game but it doesn't fit for a game covering the colonial era. Promotions as of now should be replaced by something which is technically similar but removes player intervention, i.e. we as players will no longer be able to actively promote units. Instead the stats of a ship are fixed for the time of its existence; what will change is what changed IRL, too: the training level and combat experience of your crew. Thus a ship will have only 3 'promotions' for the entire game: "Officer training", "Crew training" and "Shipbuilding traits".
"Officer training" will represent the combined effects of naval doctrines and the rising professionalism of your naval officer corps ("naval tradition").
"Crew training": untrained (=newly built) - trained (1 crossing or 30? ocean plots travelled) - capable (3x of trained) - experienced (3x of capable) - veteran (9 xp gained in combat) A ship with a 'veteran' crew won't have 5 promotions, there would still be only one: "Crew training", i.e. only its bonuses will change over time.
[An additional one could be "Shipbuilding traits" if we want to further differentiate the stats of naval units. Then we could slightly variate these by introducing national shipbuilding techniques which would force us to trade-offs between the overall sturdiness of a construction, its combat strength, its size and cargo space and its sailing speed.]
army units
"Drill" (similar to naval "Crew training")
"Discipline" (green - trained - experienced - veteran - professional) should be a major factor in deciding battles which divides raw recruits from battle-hardened Elite soldiers. We might include the effects of "Officer training" here, too.
"Terrain familiarity" (unfamiliar - accustomed - specially trained) will be the decisive factor for your army units in winning the WOI if you can lure the Royal Expeditionary Corps into the wilderness.
Battle tactics and formations on land saw more changes, particularly the development of linear infantry tactics post-1648 had a massive impact on the type of infantry units and the tactics employed on the battlefield. Your own battle experience will not contribute to these developments but it'll decisively influence when you lose your unfamiliarity with the terrain types of the New World. Being unfamiliar with a certain terrain type will give your soldiers a negative bonus (defense and attack). After several combats in this terrain type [simply counting combats or taking xp gain into account] you'll lose this disadvantage (bonus on defense, but none on offense). Once your soldiers have learned to use a terrain type in battle to their advantage you'll gain a significant bonus on defense and also on offense. [A full-scale Indian War and lots of combats versus Indians, i.e. by learning from your enemy, might be another requirement before you can "research" advanced terrain familiarity.] You'll never learn this from your king but the (early!) unfamiliarity might be removed by knowledge gained from friendly Native tribes or allies. This knowledge can also be obtained via certain veterans offering their services as FFs. [We'll have to carefully decide if we want to give advantages to troop types which are not meant to fight in that terrain, e.g. cavalry and all units using line tactics.]
[this is actually not part of my proposal but just an idea to spice up combat) 'Battle tactics': If you're familiar with HOI2 you'll remember having a HQ, commanded by a field marshall or general, as part of your corps/army could give you access to random bonus effects in battle which were mostly beneficial. If introduced 'Battle tactics' would be actually more like 'Battle formations'. Once "researched" they could be taught to your army units (by laying 3? months in garrison and be trained) and randomly used in battle vs the enemy to create a paper-scissor-stone game. Think about column vs line, or the charge of cavalry vs the square of infantry (or worse: line). Every army unit would have a standard method of attack, native to its type, usually: Charge! --- This is just an idea yet, I'm not sure if it's worth going along that route.]
inventions & Native tribes
The Native tribes of the Americas have a huge tactical advantage versus your soldiers and colonists: their terrain familiarity! Ceteris paribus this 'promotion' would make their warriors unstoppable. But actually they also fought at a disadvantage! Why? Well, lets say unfamiliarity with horses, guns and cannons. They were also not accustomed to European battle formations and tactics. Fighting versus your (and the other ais) units will teach them over time [the hard way] to overcome these unfamiliarities. By getting accustomed to horses and horse breeding they will eventually turn these into an advantage. But by then they'd have lost their numerical advantage.
I'm not proposing that the Natives should be playable but they definitely need their own "tech" screen, well, sort of. To have the Natives as the fearsome enemies which they actually were during the time span of the game they must be able to adapt to new technologies and tactics. It should be prevented that the Native tribes become too quickly a punching bag or, worse, laughing stock.
unfamiliar New World crops & farming
The New World has a lot of crops to offer which are unfamiliar to your fellow Europeans. These should be marked as "unknown" on our "tech" screen. Either contact with Native tribes or a bonus resource right next to our colony will give us first knowledge but we still won't know how to grow the crops. More contact with Native tribes, especially those that offer to train our colonists, will be very helpful to eventually grow the crops on your plantations. [A trained colonist or a converted native should be essential.] There are also crops, e.g. sugarcane or coffee berries, which are not familiar to the New World but are already known by other Europeans which will bring those to the New World. They should(?) have prior knowledge.
interweaving manufactured goods with technological progress
Extensive production of a crop is important for the production of manufactured goods based on this crop. A high production of the associated manufactured good can give you a head start on the introduction of new production processes, i.e. larger and better buildings. An improved production process can't be invented earlier than its original date but the number of goods produced by using the earlier production process [threshold required] will determine the sequence of when the invention will be made. [distributed over 5/10 years?] There should be another threshold of produced goods until a delayed invention should be possible. You'll have to do something ingame to reap such an invention. This is a difference to CIV tech trees which can usually be researched in their entirety.
plot improvements
(Most of the) plot improvements and the large versions of them should be handled similarly. They should be dependent upon the actual production of crops and additionally upon knowledge gained from the Natives.
pioneer actions
Some pioneer actions and also the time needed to complete plot improvements could be handled similarly.
absence of tech trading
"Techs" can not be traded. The only option to acquire the knowledge represented by a "tech" is to seize a rival colony which either produces an unknown crop/good, has unknown production buildings, employs unknown specialists or is surrounded by unknown improvements. Then a technology transfer will happen which - depending on another trickle down delay - will allow your original colonies to benefit from your rival's "research".
re trickle down delays
To slightly randomise new inventions and their spread we might rely on a trickle down delay. Using such a delay is a bit tricky since it might hamper the player more than expected. Although a fixed delay is easier to set up I'm wondering if we might let the level of education have a hand in this. Unfortunately, we don't have a measure for the literacy rate which would fit perfectly here.
thresholds versus difficulty level, map size & game speed
Thresholds could be balanced by the size of the map and also by the chosen game speed. The difficulty level OTOH should influence thresholds only on a very minor basis since most of the "techs" are already limited to being "researched" past a certain date although for discoveries we'd argue in favour. Nonetheless, the balancing of thresholds is not a minor task...
[Eras should not play a prominent role re "research". Since eras are ATM only used in the background to determine the lengths of game phases they should be kept invisible. We might rely on eras to invisibly split the FF screens and thus introduce a steeper cost increase for the first FF in the next era. If we group FFs according to their time of activity and distribute each of them to their era we can even think about randomising the order in which they become available thus making perfect plans less valid. Expanding on that thought and taking into account that there are far more interesting alternative FFs not included in the mod we should think about having a surplus of FFs for each era from which the actual FFs are picked.]
[IMHO a tech tree as known from CIV should be avoided at all costs since it doesn't really fit to the time frame. There should be no research points and no active research by the player. We don't need another mini-game as a time sink. Turns in mid-to-late game take already too long.]
In the "tech" tree I envision for WTP, "research" will be happening automatically but often influenced by your own ingame decisions. Yep, you simply play the game and inventions, innovations and discoveries will happen while you play. The location of your home country, your colonies, the extent of your exploration, your colonial production and also the number of your battles fought in New World terrain will influence how many "techs" you "research". There will also be "techs" which will be made public beyond a certain date, i.e. you've heard about it in Europe. Buildings, units, improvements etc. will be unlocked by "techs" step-by-step.
inventions, innovations and discoveries
Inventions will happen circa at the historical date, maybe slightly randomised. Innovations, i.e. improved production processes, will happen at best at the historical date, but will be sort of randomised depending on the crops and manufactured goods produced by your colonies. Discoveries are the result of "your" voyages of discovery. Discoveries can happen anytime once the requirements are fulfilled. Knowledge of New World crops and terrain bonuses are 'gained=learned' depending upon how you play the game.
number of "tech" screens
I'm not sure how many "tech" screens are actually needed. Main themes are exploration (improved sailing, advanced ships), military (army/naval, improved units) and economy (unknown crops, production processes, advanced buildings, better improvements). As you see I'm favouring 3 screens right now, but that depends upon the layout of "techs". The "techs" on each screen are not dedicated to a specific era but are grouped with similar "techs". I don't know if we want to name the screens, but the names used for the eras don't fit well.
screen #1 : Exploration
The first screen is dedicated to Exploration and will have a full screen historical map showing the Americas in addition to parts of Western Europe and a good part of the African coast. The Atlantic is featured prominently and has blank fields where we today locate the prevailing winds (https://en.wikipedia.org/wiki/Trade_winds), known as westerlies and trade winds, and ocean currents (https://en.wikipedia.org/wiki/Ocean_current) of the Atlantic Ocean and the Pacific Ocean. While playing you will discover these and thus gain ingame advantages, like e.g. reduced travel times to Europe, Africa or the Western coast of America, or alternatively opening new destinations, i.e. the African slave ports.
Technically the game map is split into 6 'blocks' on each side of the American continent. We usually see that only when we try to freely choose a region in the Americas instead of a known colony for our departing ships. The game can track the regions of which we have gained enough knowledge so that we can sail directly there. The same mechanism would be used to determine which of the prevailing winds and ocean currents you might have discovered. In addition are several Atlantic crossings to/from a specific region necessary to clearly identify the prevailing winds and especially the ocean currents in that zone of the Atlantic. The discovery of ocean currents does take way longer than that of prevailing winds, i.e. requires many more Atlantic crossings, to confirm the existance of an ocean current. Their discovery should be reserved to the mid-to-late game. Keeping track of this will be done completely in the background. Discoveries will be made once you've passed the thresholds. Over time your ships will enjoy reduced travel times to all of the 12 coastal regions of the American Coast, but only if you actively explored each region. Travel times should be changed to reflect the actual distance from your home country to each region. South America and the Western coast of America will then always be the farthest away. [Sadly, sailing ships in the mod will then take far longer for their journeys than IRL. I don't know of an easy way to circumvent this.]
Such knowledge can otherwise only be gained by recruiting a founding father who is renowned for his voyages of discovery. The knowledge of these FFs is not mutually exclusive, e.g. Magellan and Drake. [Columbus had some knowledge of several of them, thus giving Spain a head start towards the Caribbean. Portugal had already made a bunch of southward travels along the African coast and thus a head start towards South America. English and French fishermen were fishing on the Grand Banks thus giving their countries a head start towards North America. We can ofc do without this previous knowledge since we've randomised starting locations.]
discoveries & new naval units
Once a certain number of prevailing winds or ocean currents are confirmed these in addition to the accumulated sailing experience, simply counting ocean plots travelled in the Americas and also the number of Atlantic crossings, can give you access to new hull forms, i.e. more roomier ships, like e.g. the galleon. Being ahead in exploration might lead to being the inventor of this new ship design. Staggered by their own achievements the other players will also discover this new design, or, if very backwards, they'll learn from this invention from other European sources, e.g. your home country, once a certain cool down phase has been passed (5 years?). Knowledge in your home country goes along with buyable in Europe. Nonetheless we might want to introduce a trickle-down delay to hinder the immediate usage of newly gained "techs" by your own shipyards. [Regarding naval units actually two trickle-down delays are required before the European colonies can start to apprehend the new "tech".]
It took a long way from the original lateen-rigged caravel to the three-masted fully-rigged ship of the 18th century so that a part of the screen should be reserved for "techs" dedicated to sails, masts and hulls. The development of cannons played an important role in the development of warships, but also highly influenced the capabilities of field and siege artillery. Not only the 18th century ships but actually all ships should require the passing of their historical build date before they can be bought (or build) to restrict them to the appropriate historical phase of the game. Due to sharp reductions in length of game turns, i.e. by going from yearly to quarterly turns, we should also add minimum build times (in months/years) for naval units to keep these realistic. The acquisition of ships in Europe should no longer be instant, but instead adhere to historical build times. To compensate we might alleviate the old CIV rule "only 1 build per city" by allowing smaller units to be build in batches, i.e. introducing building in parallel.
In total, the number of available naval units at any time during the game will be way less than now, but each ship will have its place (role/function) in the game, so no longer a good part of the ships can be safely ignored by players by simply picking advanced late-game ships ... way ahead of time. The most relevant UnitCombatTypes will be (in modern terms) flagship - battleship - cruiser - coast guard and large merchantman - medium merchantman - colonial "coastal" merchantman. This is the role/function a ship has to fit in.
inventions happen at their historical dates
Some inventions might be used as chokepoints, i.e. these will be triggered at their historical dates and thus can not be influenced by player actions. A prime example would be the implementation of the idea to have several spars tied together, thus creating the tops, instead of having one large pole as a mast. The same can be said about the development of naval tactics which is based on European combat experience. Naval tactics relate to the operational manoeuvring of formations which were interwoven with the evolution of cannons and ship designs. Ships with (same caliber) cannons arranged in full battery decks were the requirement for the firing of broadsides which led to the introduction of line-of-battle tactics. Your king will simply inform you once the Royal Navy has adopted new tactics. [ancient Halfmoon formation/galley tactics -> "Skirmish/Melee formation" -> Line Tactics (1670s) plus maybe the restrictive English Battle Instructions (~1750)] Naval tactics are important for the development of new (battleship) designs but have less influence on playing in the Americas since we have no true squadron warfare.
Naval inventions will usually be required for the introduction of improved naval designs and thus influencing their superior stats. Rarely the effects of inventions, like e.g. the refracting telescope of Hans Lipperhey in 1608, will be applied [maybe after having entered one of your colonial ports] to all existing ships. A rather different example would be the carronade, which was introduced by the Royal Navy in the 1770s. That is very late in the game and keeping in mind that it was a very powerful 'secret weapon' that it should only be available to ships of His Majesty - unless captured by you. Since the French took 20 years to copy the design your own ships won't be able to benefit from this invention.
re 'promotions'
You might seem to miss the word 'promotions' in my concept. They're almost gone. Several of them offered bonuses which were not even closely combat-related while in general the 'frequent' replacement of outdated units with more modern units leaves no place for a sub-system which heavily relies on accumulating xp, especially if it can flourish only in (rare) times of war. Having highly experienced, iconic units is a game concept which might fit for a WW2 game but it doesn't fit for a game covering the colonial era. Promotions as of now should be replaced by something which is technically similar but removes player intervention, i.e. we as players will no longer be able to actively promote units. Instead the stats of a ship are fixed for the time of its existence; what will change is what changed IRL, too: the training level and combat experience of your crew. Thus a ship will have only 3 'promotions' for the entire game: "Officer training", "Crew training" and "Shipbuilding traits".
"Officer training" will represent the combined effects of naval doctrines and the rising professionalism of your naval officer corps ("naval tradition").
"Crew training": untrained (=newly built) - trained (1 crossing or 30? ocean plots travelled) - capable (3x of trained) - experienced (3x of capable) - veteran (9 xp gained in combat) A ship with a 'veteran' crew won't have 5 promotions, there would still be only one: "Crew training", i.e. only its bonuses will change over time.
[An additional one could be "Shipbuilding traits" if we want to further differentiate the stats of naval units. Then we could slightly variate these by introducing national shipbuilding techniques which would force us to trade-offs between the overall sturdiness of a construction, its combat strength, its size and cargo space and its sailing speed.]
army units
"Drill" (similar to naval "Crew training")
"Discipline" (green - trained - experienced - veteran - professional) should be a major factor in deciding battles which divides raw recruits from battle-hardened Elite soldiers. We might include the effects of "Officer training" here, too.
"Terrain familiarity" (unfamiliar - accustomed - specially trained) will be the decisive factor for your army units in winning the WOI if you can lure the Royal Expeditionary Corps into the wilderness.
Battle tactics and formations on land saw more changes, particularly the development of linear infantry tactics post-1648 had a massive impact on the type of infantry units and the tactics employed on the battlefield. Your own battle experience will not contribute to these developments but it'll decisively influence when you lose your unfamiliarity with the terrain types of the New World. Being unfamiliar with a certain terrain type will give your soldiers a negative bonus (defense and attack). After several combats in this terrain type [simply counting combats or taking xp gain into account] you'll lose this disadvantage (bonus on defense, but none on offense). Once your soldiers have learned to use a terrain type in battle to their advantage you'll gain a significant bonus on defense and also on offense. [A full-scale Indian War and lots of combats versus Indians, i.e. by learning from your enemy, might be another requirement before you can "research" advanced terrain familiarity.] You'll never learn this from your king but the (early!) unfamiliarity might be removed by knowledge gained from friendly Native tribes or allies. This knowledge can also be obtained via certain veterans offering their services as FFs. [We'll have to carefully decide if we want to give advantages to troop types which are not meant to fight in that terrain, e.g. cavalry and all units using line tactics.]
[this is actually not part of my proposal but just an idea to spice up combat) 'Battle tactics': If you're familiar with HOI2 you'll remember having a HQ, commanded by a field marshall or general, as part of your corps/army could give you access to random bonus effects in battle which were mostly beneficial. If introduced 'Battle tactics' would be actually more like 'Battle formations'. Once "researched" they could be taught to your army units (by laying 3? months in garrison and be trained) and randomly used in battle vs the enemy to create a paper-scissor-stone game. Think about column vs line, or the charge of cavalry vs the square of infantry (or worse: line). Every army unit would have a standard method of attack, native to its type, usually: Charge! --- This is just an idea yet, I'm not sure if it's worth going along that route.]
inventions & Native tribes
The Native tribes of the Americas have a huge tactical advantage versus your soldiers and colonists: their terrain familiarity! Ceteris paribus this 'promotion' would make their warriors unstoppable. But actually they also fought at a disadvantage! Why? Well, lets say unfamiliarity with horses, guns and cannons. They were also not accustomed to European battle formations and tactics. Fighting versus your (and the other ais) units will teach them over time [the hard way] to overcome these unfamiliarities. By getting accustomed to horses and horse breeding they will eventually turn these into an advantage. But by then they'd have lost their numerical advantage.
I'm not proposing that the Natives should be playable but they definitely need their own "tech" screen, well, sort of. To have the Natives as the fearsome enemies which they actually were during the time span of the game they must be able to adapt to new technologies and tactics. It should be prevented that the Native tribes become too quickly a punching bag or, worse, laughing stock.
unfamiliar New World crops & farming
The New World has a lot of crops to offer which are unfamiliar to your fellow Europeans. These should be marked as "unknown" on our "tech" screen. Either contact with Native tribes or a bonus resource right next to our colony will give us first knowledge but we still won't know how to grow the crops. More contact with Native tribes, especially those that offer to train our colonists, will be very helpful to eventually grow the crops on your plantations. [A trained colonist or a converted native should be essential.] There are also crops, e.g. sugarcane or coffee berries, which are not familiar to the New World but are already known by other Europeans which will bring those to the New World. They should(?) have prior knowledge.
interweaving manufactured goods with technological progress
Extensive production of a crop is important for the production of manufactured goods based on this crop. A high production of the associated manufactured good can give you a head start on the introduction of new production processes, i.e. larger and better buildings. An improved production process can't be invented earlier than its original date but the number of goods produced by using the earlier production process [threshold required] will determine the sequence of when the invention will be made. [distributed over 5/10 years?] There should be another threshold of produced goods until a delayed invention should be possible. You'll have to do something ingame to reap such an invention. This is a difference to CIV tech trees which can usually be researched in their entirety.
plot improvements
(Most of the) plot improvements and the large versions of them should be handled similarly. They should be dependent upon the actual production of crops and additionally upon knowledge gained from the Natives.
pioneer actions
Some pioneer actions and also the time needed to complete plot improvements could be handled similarly.
absence of tech trading
"Techs" can not be traded. The only option to acquire the knowledge represented by a "tech" is to seize a rival colony which either produces an unknown crop/good, has unknown production buildings, employs unknown specialists or is surrounded by unknown improvements. Then a technology transfer will happen which - depending on another trickle down delay - will allow your original colonies to benefit from your rival's "research".
re trickle down delays
To slightly randomise new inventions and their spread we might rely on a trickle down delay. Using such a delay is a bit tricky since it might hamper the player more than expected. Although a fixed delay is easier to set up I'm wondering if we might let the level of education have a hand in this. Unfortunately, we don't have a measure for the literacy rate which would fit perfectly here.
thresholds versus difficulty level, map size & game speed
Thresholds could be balanced by the size of the map and also by the chosen game speed. The difficulty level OTOH should influence thresholds only on a very minor basis since most of the "techs" are already limited to being "researched" past a certain date although for discoveries we'd argue in favour. Nonetheless, the balancing of thresholds is not a minor task...