I'm thinking about making a mod that changes how cities work. IMO they're to big on the map, but have very small populations, they have little to no character, and having to manually place every single house and building doesn't really fit with being the ruler of a nation.

So I was wondering, do you have to pre-design every tile in the game, or can the engine do some of the work for you? If for instance I made all cities a single tile, but wanted to have the appearance of that tile to change depending on what buildings are in the city. Would it be possible to just have the buildings appear (like in civ4), or would I have to make a new tile for every combination? I fear it is the latter, which would require me to either do an insurmountable amount of work, or a lot of abstraction, like only showing big things like castles and walls, and add a lot of 'filler' buildings to make it look like a city.

For the record, this is just an idea at the moment, I don't intend to start working on this right now as I don't have the time. Also I think I'll wait to see what is in v1.1 and what will be done in the expansions. No sense in doing this if Stardock (although I think it's unlikely) is all ready planning to do something like it.