I would like the game to have the cities I conquered slowly (like in 5-10 in-game years) become the same culture as my faction. whenever you enter a city there can be a meter that tells you the main culture of the city and how much of other cultures' influence it as well. it will determine what is produced in the city (ex. Valandian culture city will produce Valandian armor, weapons, and troops). if a culture's influences is 75% or more, then that becomes the main culture. now there is a similar idea in this thread called Let town owners build ethnic enclaves that unlock different culture troops and trade goods, but they talk about having some cultural variety in troop/armor production that the player must actively choose to do rather than pure integration that happen naturally over time. of course the problem is that if the player likes a kind of troop from a different faction, then by mid to late game they might never see them again. the solution is when a city/village change their troop production to match the the culture, the powerful notables in the city will still produce troops of their original faction, so the player can still recruit the best troops of a dead faction (Khan's Guard, Fian Champion, Cataphracts, etc...). the only other problem I see is the fact that this can change how rebellions work, but they are just an annoyance more than an actual threat anyway, so I don't care.