Currently in the game you can capture an enemy city and that's the end of it, captured citizens are now your loyal subjects. I take issue with this and its a fault that occurs in a lot of games, not just this one. Pacifying a populous of a captured city needs more attention. Where are the resistance movements, the hit and run attacks by disgruntled citizens, where are production penalties for integrating two different races? Seriously you cant expect a fallen faction to just suddenly coexist with a kingdom faction, especially after it kills the military in that city off? Also where are the options about how to manage the new captured cities, and policy towards the inhabitants, do you want to treat them decently, enslave them, or simply commit genocide on a massive scale. I feel these should be implemented along the line. What are your thoughts? Here are my ideas.
1. Population management/integration: Newly captured cities cost double resources to maintain for a time as the new population settles in. Shorter if your faction alignment is the same, longer if different. Times are also factored in by your policies towards captured cities. However this is the "good path" and makes capturing and holding future cities easier. More about that later.
2. Cities can possibly revolt back to their previous owner, if they are close to their factions territory, or the number of troops stationed is low. This can also be factored by your military strength compared to the faction that they belonged too. Revolt possibility can also be determined by your treatment towards the people of that faction. More next.
3. "Race relations" Here we get to the good stuff, how to manage the population of the city, each has their pluses and minuses. Slavery, using the population as cheap labor/cannon fodder. This cares a production boost and cost reduction in the city, but carries a possible diplomatic penalty with other factions, and will make revolts more likely. Forced re locations: This is obvious you force out the current residence of the city to make room for your own. This carries a short term production penalty, and possibly penalties with other factions but prevents a city revolt. However it will make holding on to newly captured cities more difficult. (same with slavery) Now you can also treat the captured population decently(Which is what I like to pretend is happening in the current game version) In short this should have short term production and cost penalties as the newly captured populace gets integrated into your kingdom/empire. However in the long term it pays off as other factions see how you deal with civilians, making newly captured cities less likely to revolt.
4. Genocide. Obviously this one is plain and simple, when you conquer a city you kill all inhabitants immediately. While this one maybe satisfying in a certain sense it also carries the most diplomatic penalties and makes capturing new cities harder as the people will fight harder. The trade off is that other factions may be less inclined to fight you as they will be fearful of your wrath.
5. Scorched Earth. plain and simple you destroy the enemy city for a major loot bonus but this carries major diplomatic penalties with the faction you did the city razing too, and may also cause other factions to distrust you.
6. Race relations. There should be a population tally in cities based on what faction's citizens are living in a city. In cities you found obviously your people would be the major inhabitants but in captured cities the opposite is true. This could have economic issues as the new captured citizens get integrated however after X number of turn the new population will settle in and be "loyal subjects" and the penalties will cease.
Also a note on city sizes, obviously if you carry out the actions above on a small level 1 to 3 town the political fallout is less severe but when you use these tactics on a level 4 or 5 city the fallout is major.
Anyways these are my ideas, I am sorry for any spelling error, my spellchecker is not working. Well I look forward to hearing your thoughts on this.