Culture, and the archatextural shift feature.

[x-Krelian-x]

I know this isn't really a 'gameplay' feature, but I always liked how in SMAC when you captured a city the archatexture stayed the previous owner's, instead of shifting to the conquorer's. It just seems kind of odd the citizens keep their nationality but the buildings don't. The city graphic could be based on % of workers, or which civ's culture is higher in that city. It would kind of add to the atmosphere of the game, and help players who aren't familier with each civ's city names to remember which were who's.

Also, 'ruined' and 'abandoned' city graphics would be cool, for when cities are attacked and either fall below size 7 or is destroyed / abandoned.

[Andrew_Jay]

I think ruins are in PtW.
I like the idea of keeping the old Architecture, maybe even some graphics as it is integrated into the new, much like how you can still see old buildings and styles as you advance through the ages. Like you said, this would help the atmosphere. I remember a thread where it was debated to have city names automatically changed, but seeing who owned your cities originally is fun, and adds to the game.

[candybo]

I agree, it lends each region a sense of history. As for keeping old building styles, on one hand it makes sense (i.e. Roman coliseum). On the other hand, then people would gripe about having, I dunno, how many granaries does your town have these days?