1. Implement true simultaneous turns, and design the base game around this. This would allow for multiplayer games to actually function, rather than the bad RTS that currently exists in game.
2. Change military units from single units to larger armies, in effect bringing back unit stacking but with all units fighting as one. 1UPT has proven to be a dismal failure.
3. Consideration: Removing the concept of tiles altogether, at least at the player level. (I know in practice it is impossible to completely remove granularity on the map.
4. No longer have a concept of "working a tile" - a city's maximum yield is determined by the surrounding terrain and improvements, but hammers, food, and so on must be done by specialized laborers. For instance, a city with lots of arable land would produce more food per farmer, and advances in technology allow more population to be allocated to areas other than farming. Historically most of the human population was involved in agriculture, and it was not until quite recently that this has changed (and even then, the entire food distribution chain involves more than just those who are documented as farmers... anyway...)
5. For the love of god, don't use 1 population = 1 science. That has led to the optimal civ5 strategy being simply to find the best way to maximize population, and narrowed most of the options for building an empire. I can see getting some yield directly tied to your population, but it shouldn't be just "do this to get science".
6. Make social policies actual choices with drawbacks, rather than just benefits. If all else fails just revert to the Civ1-3 mechanic of having distinct government types.
7. No more units healing for free. If a unit/army gets damaged, it ought to need to pay for replacements with hammers/materiel, just like producing new units.
8. No more ridiculous ranged damage being risk-free. I can see some late-game units like artillery, bombers, or helicopters being able to hit from range, but nothing like archers that bombard over continents (that only apply to early armies, strangely).
9. No more unit promotions. Veterancy is the only perk that should come out of battle. Other abilities have to be attached to particular units. I can see army units being specialized upon creation, in order to add variety.
9a. Possible consideration: Rather than get new units with every era, the basic military units available would be consistent throughout the ages, and new technology like iron weapons, gunpowder, machine guns, stirrups, etc. would be represented with promotions.
10. Tie production to a lot more than currently exists. Production is already pretty important, but there are too many things which can be bypassed with gold like unit upgrades. Consideration: Building upkeep is not paid with gold, but with hammers, so a city that builds libraries and such does so at the expense of labor (in addition to the diversion of population to research specialists).
11. No more unique units and especially no more unique abilities with crazy perks, i.e. Poland in Civ5 which is just ridiculous.
12. Bigger cities and more population in general. City populations should somewhat reflect real-world population growth and sizes. No more triangular population growth, one population unit = 1000, 10000, or however many people is sufficient. I would think 1000 is a fair number, and would go so far as increasing the population cities start with. A late-game city could have 1000 population units to allocate or more, though some of those will malcontents.
2. Change military units from single units to larger armies, in effect bringing back unit stacking but with all units fighting as one. 1UPT has proven to be a dismal failure.
3. Consideration: Removing the concept of tiles altogether, at least at the player level. (I know in practice it is impossible to completely remove granularity on the map.
4. No longer have a concept of "working a tile" - a city's maximum yield is determined by the surrounding terrain and improvements, but hammers, food, and so on must be done by specialized laborers. For instance, a city with lots of arable land would produce more food per farmer, and advances in technology allow more population to be allocated to areas other than farming. Historically most of the human population was involved in agriculture, and it was not until quite recently that this has changed (and even then, the entire food distribution chain involves more than just those who are documented as farmers... anyway...)
5. For the love of god, don't use 1 population = 1 science. That has led to the optimal civ5 strategy being simply to find the best way to maximize population, and narrowed most of the options for building an empire. I can see getting some yield directly tied to your population, but it shouldn't be just "do this to get science".
6. Make social policies actual choices with drawbacks, rather than just benefits. If all else fails just revert to the Civ1-3 mechanic of having distinct government types.
7. No more units healing for free. If a unit/army gets damaged, it ought to need to pay for replacements with hammers/materiel, just like producing new units.
8. No more ridiculous ranged damage being risk-free. I can see some late-game units like artillery, bombers, or helicopters being able to hit from range, but nothing like archers that bombard over continents (that only apply to early armies, strangely).
9. No more unit promotions. Veterancy is the only perk that should come out of battle. Other abilities have to be attached to particular units. I can see army units being specialized upon creation, in order to add variety.
9a. Possible consideration: Rather than get new units with every era, the basic military units available would be consistent throughout the ages, and new technology like iron weapons, gunpowder, machine guns, stirrups, etc. would be represented with promotions.
10. Tie production to a lot more than currently exists. Production is already pretty important, but there are too many things which can be bypassed with gold like unit upgrades. Consideration: Building upkeep is not paid with gold, but with hammers, so a city that builds libraries and such does so at the expense of labor (in addition to the diversion of population to research specialists).
11. No more unique units and especially no more unique abilities with crazy perks, i.e. Poland in Civ5 which is just ridiculous.
12. Bigger cities and more population in general. City populations should somewhat reflect real-world population growth and sizes. No more triangular population growth, one population unit = 1000, 10000, or however many people is sufficient. I would think 1000 is a fair number, and would go so far as increasing the population cities start with. A late-game city could have 1000 population units to allocate or more, though some of those will malcontents.