Status: Gathering Ideas and Feedback, Recruiting

One of the things that have always annoyed me in Civ is that progress is the only way. There are no real periods of general decline of population, knowledge, et cetera. I would really like to do something about this, but I need ideas. Anyway, I hope such a mod will increase the challenge of playing once you have established a lead in technology and/or land size.

I'd like to hear your ideas. Both about what I'm presenting here and you own thoughts. It will be much appreciated!!

In this thread, I will format new major concepts (basic concepts like culture or resources) to be bold, and minor new concepts (like a promotion or scripted event) to be cursive. For easy reading, please stick to this convention in this thread. Thank you!

This is what I'm thinking of:

Make it possible to expand quicker, so you can have early big empires: Civ4 currently fails to show empires like the Roman, Greek or Mongol empires. If a player reaches such a size, it is late in the game, and the winner has pretty much been determined.
To compensate for the early growth, I want to introduce a couple of new concepts : Decadence, Knowledge loss, and Cohesion. Maybe we could also expand the golden age system ( see farther below, at 'Additional Thoughts' )

Decadence: Many great empires were destroyed from the inside just as much as from the outside. E.g. : Romans, Ottomans. If a civilization is too self-important about past achievements and fails to innovate, it becomes a living fossile. While it was on the rise, there was a goal, a just cause, there were enemies, there were great leaders, a lot of new ideas, and great achiements were made.

Decadence
In Civ terms: Low maintenance and decadence as long as borders keep expanding, keep exploring, there are rivalling civs, you get Great People regularly, and build some wonders. If you conquered your part of the world, say, you conquered your only neighbor, your isolation will cause extra decadence. If you fail to keep the spirits up, you will fall into decline.

Effects:
Decadence level rises and takes up part of your production and trade. Great people rate and culture production are also reduced, as well as worker rate. Improvements and buildings tend to fall apart, military units risk a chance of losing experience, deserting (damage or disbanding effect) or low morale (-x% strength promotion). If the decadence lasts, whole cities might revolt to neighbours or barbarism. To get out of this depression/dark age, you will have to complete a few wonders or culture buildings, get some great people, get new civics, or lose some cities to a new enemy. Since decadent nations are weak and a good target, the latter is supposed to be an 'easy' but expansive solution to decadence. I hope that this will more closely model 'real' history.

Knowledge loss
When in decadence, or when the science rate is very low and you are not currently investigated that particular branch of the tech tree, your people may start to forget some of your discoveries! Especially techs that are of an Era you only just recently entered are in danger. For example: if you discovered most of the Classic Age techs, and have entered the next age by discovering Machinery and then go to research Calendar (which is Classic Age), Machinery runs the risk of becoming forgotten.
I'm not sure how to implement this, if it can be done, whether to make the forgetting gradual and how to show that. I also don't know what factors should influence the rate of forgetting. I guess libraries, academies, universities and the like should reduce the risk.

Cohesion
Cohesion is a measure for the unity of your empire. Remote or overseas territories, or cities that are not connected to your trade network should get an extra penalty.

Effects: Population loss, risk of revolt, collapsing infrastructure,Barbarian Hordes on the outskirts of your empire?

Additional thoughts:
Maybe risk of revolt can be implemented by granting cities (improvements that generate) barbarian culture.

Also, I was thinking that maybe the level of decadence could be implemented by making more ages like the Golden Age. Now, the upper right corner of the interface displays a gold coin and the number of turns that the Golden Age will last. Image different coins and different effects for other Ages.
After all, many cultures like the Greeks, the Romans and the Indians thought the world cycled through many ages, with the Golden one generally just being the best phase. The Persian 7 ages would be especially cool, I think, but less might do as well.
http://home.student.uva.nl/jeroen.kools/agestable.jpg

[u]Interested to help:[u]
- BrokenLegion (xml and buttons/icons)


Like I said, I would very much like to hear your thoughts and comments.

Yours,
Junuxx

Also, if people feel enthusiastic and would like to help me with python programming or making some buttons/icons, you're welcome!

I like the idea, it is all to easy to dominate the game early on. From then on even I begin to get a bit cocky. To have this reflected in my empire would be good.
Forgetting technologies doesn't quite work for me though, except for isolated incidents this hasn't really happened in History. Another possibility is 'wrong' technologies. My thinking here is basically ideas like a flat Earth etc, researching them could be easy and give limited benifits but start to act as an anchor if other civs research the right idea. It's a bit rough but worth considering, and it would be possible, modding the Tech XMLs.
An area that was (partly) in previous games is factions or new nation spring off from yours. If you were in such terminal decline this could be a good feature though I'm not sure how you'd implement it.
I'll be watching your developments with interest.

Flat Earth is a great idea :lol:
Wrong technologies is definitely something to look into.

I don't think I agree with you on forgetting, though.
Some examples:

After the Hyksos or Sea People raided the Eastern Mediterranean around 1100 B.C., the Mycenean Greeks completely returned to the Stone Age. Among other things, they completely forgot how to write!

The steam engine has been invented by the Greeks in 60BC (the inventor Heron is featured in Civ4 as a Great Engineer) and in China around 30AD.

In the Dark Age in Europe, much knowledge about sanitation, architecture, drama, education, astronomy, physics and math was lost or virtually lost. With virtually lost, I mean that although some monks read the Ancients's books and knew the stuff, no applications existed.

I think I read somewhere that Civ III's golden ages were originally going to be dark ages as you suggest, but they decided it wouldn't be fun.

I think I read somewhere that Civ III's golden ages were originally going to be dark ages as you suggest, but they decided it wouldn't be fun.

Oh, I didn't know that. Interesting. I can imagine why they thought that. But maybe their approach was simply wrong. My intention is to make the game more interesting and challenging for a leading/dominating/stagnant civ, but not to paralyse a nation.
That would indeed only make things more boring.

I take your point about forgetting, I didn't know it happened so much (it's good to learn). Other wrong Techs could be 'old medicine', leeches and the like. It could give a happiness bonus (people think they're cared for) but when real medicine is discovered the bonus goes and is replaced by universal unhealthiness.
I also thought about random events like natural disasters and fires etc. I think their pretty straight forward, what would be really good is if you could make them optional ever game like barbarians.
When the made idea shouting phase is over, I'd be happy to help button wise or on XML (I'm scared of Python) I'll go now, just finished my Armenia and Azerbaijan Civs, gonna try them out.

I really like the idea, and would like to see it implemented in a mod, but it's tough to say how it could be modeled. It would be interesting to have Civ reflect the actual development of civilizations but I'm not sure it can. Civilizations rise and fall in real history much more often than they do in Civ. There is also a lot more random chance in real history than in Civ.

Some ideas:
-One thing to consider is bringing back the old "civil war" from Civ II where if your capital is taken, then your outlying provinces revolt and become part of the barbarian faction.
-The barbarian spawn mechanism should work differently. Instead of having a single warrior appear out of the FOW every 2 turns, there could be various huge barbarian uprisings much less frequently but strong enough to wreak havoc on an empire. Random luck, and it sucks if your civ takes the worst of the barbs, but that's the way civilizations have declined and fallen.
-Cities could potentially revolt to barbarian factions if their unhappiness is high.
-The amount of food needed to grow a city could be reduced to simulate quick growth of societies and also to increase the need to manage happiness/health within your empire or face revolt.
-Natural disasters like drought, flood, plague, etc could occur randomly and wreak havoc on empires.

I would suggest moving away from the standard civ research model into a tech-spread model. What I mean by this is that, rather than have every civ research every tech by itself (or trade for it), one civ discovers a tech, and it slowly spreads from there to other civs. You'd need to set up zones of spreading (each continent not reachable by another continent without crossing sea or ocean), and allow one discovery of any given tech within each zone. So that (to use the real world as an example) Asia-Africa-Europe would be one zone, North and South America another, and Australia another. This will ensure that (real world example again) Sumer can discover writing and have it spread to Egypt, India, China, etc., but not to the Iroquois or Aztecs - they'd have to discover it on their own. Also note that you shouldn't artificially restrict someone from crossing into another zone and spreading technology. If some civ discovers the tech to cross seas, let them go spread tech elsewhere.

So how does research work in a tech spread model? Each civ produces beakers, which get pooled and divided within each spreading zone, and applied to every available technology that can currently be researched. In essence, you could look at it as though each zone behaves similar to civs currently, and each civ behaves like a city currently - except that each available tech (the zone has the prerequisite for) is being researched at once, rather than one by one. In-game events affect the percentage of beakers applied to each available tech. So for example, if a war breaks out, the percentage of beakers going to Bronze Working, might jump from its previous level of 10% to 25% (of total beakers produced in that zone). Or, if a civ enters a golden age, the percentage of beakers going to a cultural tech like Music might jump in a similar way. This will have the effect of warlike zones advancing in techs of war and cultural zones advancing in techs of culture - at the cost of other techs coming very slowly. Pushed to the extreme, this could be very bad for that particular zone in the long run.

Moving to such a system would also require implementing education levels. Libraries, temples (religious centers also tended to double as learning centers), universities, some wonders, etc. as well as the science slider increase education levels. They give larger bonuses the longer they've been in continuous existence, meaning older libraries give larger bonuses than new and the longer you maintain a given science rate the bigger the bonus. Education levels within a zone determine who is the most likely to discover a tech. The key there is "most likely", there are no guarantees - even the least likely of civs could develop gunpowder and turn the tide of the game by conquering faster then the tech could spread.

And how do techs spread/how are techs acquired by civs for their own use? If you discover the tech, you have it to use immediately. If you're waiting for it to spread, several factors are involved. Your level of connection with the discoverer (trade connections, Open Borders, regard, etc.) and your education level are the biggest players. Traits, civics and science level affect it as well.

Anyhow, I've already written quite a bit, so I'll just leave it at that for now. Feel free to brainstorm and continue that model if you desire.

some ideas:

1.Ability to hire mercenaries
2.Religion spreads more quickly in decline (As with Christianity in the Roman Empire)
3.Large empires can fragment into smaller kingdoms (With the original owner retaining core cities), introducing new players (From some of the new civilization mods perhaps?)
4.Plague as a random event
5.There are good periods as well as bad

I like the idea of dark ages included. I dont think this would be so hard to mod in. I think that dark ages should be more frequent than golden ages maybe 3 or 4 to 1. Also I think that we need a good desease moddle(better than civ3) that would be more devestating. I think that these aspects of the game should slow techno research almost to a stop befor after a period of time you could recover. Deseases need the ability to completely destroy cities, and random computer not barb civs spawn in open area.

@BrokenLegion:
I agree, natural disasters are an excellent and realistic way of causing a setback. I'll put you on the 'willing to help'-list.

@suspendinlight:
Yes, indeed there are some parts I proposed that might be rather though to code in. But I'm up to a little challenge! ;)
I too liked the civil wars in Civ1/2. The problem with it has always been that it can't happen if all civ slots are full.

@alms66:
Not sure about tech-spread, really. Or maybe it should be extremely limited. Only let it spread to neighboring nations with the same religion, only if you have very good relations, and only if applications of the tech exist in cities near the border.
But altogether, I think it's better to focus this mod on setbacks&decline (and some positive things to compensate the slowdown, like cheaper early expansion)

@NuclearElephant: (cool nick)
Can you explain whatt the use of hiring mercenaries would be? I don't really see the point.
I agree with you on your other points.

@tlucky4life:
I don't know about cities being destroyed by disease. Reduced to one is frustrating enough, I think, and people hate to lose cities. It is supposed to be fun, after all.

What do you think of introducing the kind of ages from the table in my first post? Default could be Brass Age, and you could go up to Silver and Gold or down the ladder towards Iron and Clay, depending on your actions.

New idea: When you're not in a dark age, you should be able to Salvage city ruins for beakers, culture and/or cash.

Many of the effects your looking for could be accomplished by adding a cumulative happiness and culture penalty based on score. For example, you could have a penalty of -1 happiness and -10% culture for every 20 turns that your empire is the score leader, and remove the penalty at the same rate if it is not. This doesn't do everything your looking for but it has the advantage of being simple.

I like the ideas of empires collapsing. Perhaps if civilization A gets larger than the average land area of the other civilizations, then civilization A runs the risk of having various parts of the country seceed. Perhaps beyond a certain distance from the capitol or a territory that is seperated from the home territory by water or other civilizations.

I like all the ideas displayed here. What really annoys me in Civ is the fact that empires die. that is SO UNTRUE, take any empire, the Babylonian, Egyptian, Hindu, Aztec etc. they all returned after death. I think we should have empires reborn when the resistance becomes too high

@NuclearElephant: (cool nick)
Can you explain whatt the use of hiring mercenaries would be? I don't really see the point.
I agree with you on your other points.


Not sure why that came to mind. I just remembered it as one of the things that characterized the fall of Rome. Now that I think about it though, you're right, it doesn't have any meaning for gameplay.

-NE

Really nice idea, should massivley change the difficulty of Civ (without giving stupid benefits to the AI). I like the idea of the possibility of your civ/other civs breaking up into small factions. Perhaps if one other civ breaks up, then part of the empire (Capital/nearby cities (ones with highest culture?)) is retained by original owner, some cities go to allies (only ones closest to allied cultural boundries) while all others go over to barbarians.

One Q. with regards to barbarians: Do Barb states interact and co-ordinate? Can different cities combine attacks or do they work independantly.

Regardless, the Greek World mod with vanilla civ has a few Barbarian states that appear not to be imediatley hostile, are not all black in colour, and are impossible to enter into diplomacy with.

Implementing decadence into a game like Civ is certainly no small feat--otherwise, I'm sure Sid Meier and all the other pros would have put it in long ago.

However, I think an idea with potential would be something like the corruption system from previous games; one that is built upon the concept of law enforcement (I can already see Hammurabi's Code being a great wonder). The usual causes (city size and distance from capital), along with civics, and possibly different specialists (under certain circumstances) could increase corruption; the palace, Forbidden Palace, Versailles, courthouses, "district offices" that require X number of courthouses and have a limited palace-type effect (available with Civil Service probably), civics, educational facilities, and once again certain specialists (once again given certain conditions), and even a new type of specialist, could counteract it.

You're probably still wondering what I mean by specialists causing corruption. Really, I have two angles here, both of which are actually somewhat related... The first one is to tie this corruption system and the religion system together through the whole church and state thing.
Provided there's a state religion, preachers could generate corruption to represent that which occurs in a large and powerful clergy. Of course, the organized religion and theocracy civics would only augment this effect. Multiple religions in a city, on the other hand, would lessen it to an extent.
The other approach would be the implementation of a class system, which would have its effects augmented by the caste system civic, but exist regardlessly.
The class of any part of the population would be determined by a number of factors. First off, any laborer working a tile that is unimproved or has a farm, mine, windmill, camp, lumber yard, watermill, well, offshore platform, fishing boats, whaling boats, quarry, pasture, cottage, or hamlet, together with any citizen specialists, would be considered lower class. These are the people who are typically the victims of corruption, and so they work less efficiently and become more unhappy as corruption increases--especially under civics like slavery and serfdom.
Upper class would include certain specialists under certain civics (merchants under mercantilism or open market, or preachers under a state religion, as examples), as well as any laborer working a plantation or winery. These are the members of society who have a knack for becoming corrupt in order to maintain (and increase) their wealth and power. This effect would also be further strengthened by civics like vassalage and hereditary rule.
The middle class includes any laborers working tiles with villages or towns, and any specialists not including citizens and those who are upper class due to civics (and, err, not to mention a new specialist type I'll get to). This class does not create nor suffer from corruption, meaning that having a big, strong middle class will result in a (more) stable society.

Now for that specialist I mentioned a moment ago. Courthouses, jails, and the afore-mentioned "district offices" could allow you to have police specialists who are able to reduce the amount of corruption in their city, which of course would be rather valuable. These specialists would have a twist, though--there would be a threshold, its level most likely dependant upon your civics, that would cause them to become less effective or even actually produce corruption; a natural result of the law enforcement establishment becoming bloated or oppressive from wielding too much power. Even worse, once the police is corrupt, it causes the courthouses and "district offices" to become less efficient, and even generate corruption themselves if things get way out of hand (just imagine the Forbidden Palace increasing maintainance costs--ouch!). Anyway, I'm sure you can already see the relatively low threshold that would exist under bureaucracy, or especially the police state civic.

Lastly, we're talking about a system to help facilitate the decay of an entire empire, so it's only natural that corruption would be able to spread from city to city. Although simply having a city's corruption become a factor that contributes to corruption in nearby cities, that's just not fun enough. It should also spread via trade routes and have the strength of effect based in culture--just imagine an international incident taking place because corruption in your cities is rising due to trade routes you have with influencial foreign cities!

At any rate, if I spend any more time on this monstrosity of a post I'm going to end up crying myself to sleep or something. I swear, I get too carried away all the time :cringe:

So, I'm out! Good luck with your endeavor, and hopefully all this disorganized crap I spewed into this corner of cyberspace will help inspire you or something.

@Mug:
The Barbarian State is one whole. If you play a Terra map, you can see they sometimes build roads between cities, and they defend and attack together.
The 'barbarian' states in the Greek World scenario aren't actually barbarian. Those are called 'minor civs'. I don't think it's a very good idea to use them because they would include too many civilization slots.

@A Silly Goose:
Thanks for the long post. Although I like the lower/middle/upple class idea, I'm not sure if it would give the effects I have in mind. I'm afraid that this type of corruption would be a continuous burden, instead of a relatively short period of decline and disaster. Spectular and swift shifts of power, rebuilding after a disaster and trying to regain your position is supposed to add to the fun.
I think an lower/middle/upper class system would be very cool to have in a 19th century scenario, though.

@alms66:
But altogether, I think it's better to focus this mod on setbacks&decline (and some positive things to compensate the slowdown, like cheaper early expansion)


Well, obviously, and that's why I posted, because moving to a tech-spread model would help improve Civ's ability to model setbacks/declines and would help civs that have fallen back to gain a lead in a hurry, with a little strategy and luck.

Setbacks could occur when temples, libraries and other education level enchancing buildings are destroyed through war, rioting, succession (the loss of a major "science" city can be disastrous), etc. This would give another route to having a setback occur, other than the simple on/off Dark Age mechanism, and at a slower rate. Essentially, the more ways you have for setbacks to occur, the more likely they are to happen.

And this quote from myself explains the possibility of a comeback:
Education levels within a zone determine who is the most likely to discover a tech. The key there is "most likely", there are no guarantees - even the least likely of civs could develop gunpowder and turn the tide of the game by conquering faster then the tech could spread.

Anyhow, I understand your reluctance, as a tech-spread mod would be a mod unto itself, with the need for lots of testing and balancing - probably just as much as this mod without it.

Could decline be at least partly modeled as a sort of negative culture? Perhaps under certain civics, certain buildings produce a negative cultural value in addition to their normal effects. To offset this, other buildings produce an increased amount of culture under a given civic. For example, under theocracy, temples of the state religion produce both happy faces and doubled culture. Cities in your empire with other religions and their buildings, however, produce happy faces and a negative cultural value, representing the fact that, on the one hand, the alternative religious cult makes some people happy, but is also generally corrosive to the cohesion of your society as a whole. The good effects could be increased the farther the city is from the capital, or perhaps in this case, the holy city, and the negative effects could be increased as distance to the cult's holy city decreases, and the influence of the cult at large in the world increases. To offset the negative culture, you must construct buildings that promote your own culture (The exact amount contributed also proportional to the influence of your state religion, perhaps). Due to their lack of integration into your culture, cities with zero, or negative culture, could have a chance to spontaneously revolt to a barbarian state in addition to their chance to mutiny to nearby civilizations. Once one of your cities becomes a barbarian state, what was to you negative culture, instantly becomes positive culture to them. Any rebellion adds an increased chance of further rebellions in the near future. Of course, barbarians would probably have to be able to build everything to avoid their own cultural buildings being destroyed on revolt (Or maybe only the positive culture buildings are destroyed), and to give them a chance to build up.

In the end, a large civilization would have to have a really strong culture and well chosen civics to hold itself together.
This kind of system could make things really interesting. I hope this is helpful.

-NE

Yes, I was thinking about using building that produce either negative or bararian culture. The latter would simplify the process of the city revolting to the barbs, I think.

Overall, Civ4's research model is twice as good as Civ3's. Within the confines of the game as it is, the 'correct' way (as the game designer's may have seen it) of diminishing a civ is with culture; subtracting, adding barabarian, etc....

On the other hand, what you are proposing, and which with I agree with tremedously, is a more dynamic system than culture. There have been some great ideas here. A Science spreading model would be even better than the current one, although I have no idea how to Mod it in.

One suggestion of mine would be a penalty for researching under 50%. For each 10% under 50 you get a point against you. Each time these points = 2, 5, 10, 17, etc... your civilization would lose a technology. Of course, the general research speed may be increased a little.

Another suggestion is to add a penalty each time you enter a new technological age. Each time you research into a new technological era (Renaissance for example), each of your cities has a 50% chance of reverting to a 'Minor' civ. The new civ begins with all technology from the most recently completed technological age (most likely Classical or Medieval in this example). Civ expansion would have to be greatly increased in order for this to work effectively.

OPTIONAL TECH-SPREAD READING:
Well alms66, I'm glad you buy into a new tech-spreading model. I'll offer mine and you can see if you like it. Rather than expanding research pools to include regions; expand the research pool to the entire world yet reduce the effects to individual cities. This is to say that each turn 1 city is chosen based on beaker output to 'earn' a technology. This technology can spread along trade routes and over land (much like a quicker, religion model).

On the next turn another city will have the option and may even pick the same technology which will now spread from two places. This will help create the dichotomy evident in history between Old World civs and New World civs, as Old world civs will be able to go faster through technology and conversely put more effort into research, strangling the New World civs from research oppurtunities. Just my idea, comment if you would like.

Sorry to hijack the thread, but I came up with an idea that includes a dark age option. It originally came from Civ3, with the "Mobilize for War" option you got from Nationalism.

Using Civics, it shouldn't be too hard to put in this sort of short-term boost/penalty system. Just throw in an automatic switcher script at the start of each turn, add in the random chance of going to the dark ages, and presto, you've got a "State of the Nation" system.

Normal: The default civic. Automatically switches to this after 20 turns in any other SotN civic (10 if the last civic was Reniassance), and can't be switched from again until another 20 turns have passed (unless the last civic was Dark Age).
No other benefits or drawbacks.

War-Time: Available with Military Tradition (maybe earlier). +50% bonus to unit production, but -50% penalty to non-military buildings. Automatically switches to "Normal" if not at war.

Expansion: Available with Nationalism. 50% bonus to producing Settlers and Recon units, but -2 health in each city.

Reformation: Available with Theology. +50% culture in each city, but -2 happiness in each city. Religion civics have no effect during this time (not sure if this one is possible).

Renaissance: Available with Education. +50% science and Great Scientist birth rate. This civic only lasts for 10 turns instead of 20. Does not increase the chance of a Dark Age.

Dark Age: Available from the start.
-25% production on everything, -50% science rate, and -100% GP birth rate.
Cannot be switched to manually, but can be switched to at the start of each turn randomly. Overuse of other SotN civics increase this chance, as well as low research, low culture, or high maintenence costs.
Resets SotN turn timer when activated (so if you're in War-Time for 15 turns and hit a Dark Age, you have to endure the full 20 turns of the Dark Ages), but on the plus side, you can switch to another SotN civic immediately after getting out of a Dark Age (rather than spending 20 extra turns on "Normal").

That's a pretty interesting idea. Although, maybe only a Golden Age and a Dark Age would be needed. Plus this could boost the usefulness of a Golden Age.

OPTIONAL TECH-SPREAD READING:
Well alms66, I'm glad you buy into a new tech-spreading model. I'll offer mine and you can see if you like it. Rather than expanding research pools to include regions; expand the research pool to the entire world yet reduce the effects to individual cities. This is to say that each turn 1 city is chosen based on beaker output to 'earn' a technology. This technology can spread along trade routes and over land (much like a quicker, religion model).

On the next turn another city will have the option and may even pick the same technology which will now spread from two places. This will help create the dichotomy evident in history between Old World civs and New World civs, as Old world civs will be able to go faster through technology and conversely put more effort into research, strangling the New World civs from research oppurtunities. Just my idea, comment if you would like.

Ok, now this has the smell of a thread-jack situation here... If you want to start a new thread to discuss a tech-spreading model, feel free, I'll participate. Or if you want to PM me to discuss it, again that's fine. But this should be our last 'off-topic' post on the subject.

Anyhow, regarding your model - it's definately simpler than what I proposed, and it could work well (just a guess, I'd have to play it to say for certain). One thing though, is that you couldn't have techs given every turn unless you redesigned the tech tree to be much larger, as tech research would be far too quick then, I believe.

I like the idea of civil wars and empires breaking apart, can it not have reserved civs for this. it would add another level if these civs could join together in a union or conferdation and become one again

I would like to see the following system.

[N.B. I have no clue how Python works, but learning XML wasn't too taxing, so if no one else would be willing to do this and if anyone knows if/how this would be possible and it's not *too* hard, I might give it a shot]

Non-state religion = chance of barbarian culture bomb (great artist) which flips the city to the barbs.

Non-state religion building = chance of barbarian culture bomb (great artist) which flips the city to the barbs.

So if you have a city with 2 religions, 1 your state religion, not much chance.

But when those religions start piling up, and when your cities are large enough that you need those non-state religion buildings for the happiness, then the risk of culture flip to barbs starts becoming more apparent. And of course, the more cities in your empire, the more "die rolls" will be made so the more likely you are to get a culture flip. And also when you conquor another civ, chances are they have a different religion so chance of culture flip.

Finally, suggest that this chance would be halved under theocracy, and would entirely disappear once you switched to free religion.

I would suggest as chances to flip maybe 0.1% per non state religion, +0.2% for a non-state religion temple, +0.4% for a non state religion cathedral.

Based on the games I play, I generally have ~10 cities, if I wasn't spreading every religion to every city then I guess later in the game I'd have maybe 10 isntances of non-state religion, which would mean if I wasn't building non-state religion temples I'd have a culture flip to barbs every 100 turns. Which is quite a long time, but just breaks the monotomy a bit. You know you get lost in a builder sprint, where you're just piling on the buildings and the research? Would just mix things up a little.

Also note that, although I'm not sure exactly how the culture flips occur, I'm guessing that your older, more prominant cities would be able to withstand a barbarian culture bomb. Their influence would be reduced, but that's not so out of line with the idea of decaying empires.

Oh, and this might make a cultural victory very difficult. But who cares about cultural victory? :)

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About science spread. It does work very well in Europa Universalis 2 (EU2). It's generally a better mechanism for modelling science as it prevents those unassailable tech leads. But I think it's too difficult to do in Civ4?

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I'd love to see some civil war chances. IMO, it should be a small chance, random event, no way to prevent it (otherwise you'll just prevent it so it never occurs... so what was the point in having it?). It should only be a chance for the top ~3 civs on the scoreboard.