Civ3 cities imo were in many ways a lost cause from the start, due to the massive size of them. While compared to some other games (for example Knights of Honor) they are small, they still are too huge for someone to work a 2d model. In civ2 in contrast to that the size is small so one can pretty much finish a set with eight buildings which themselves would be small. In civ3 there are 10 buildings in the metropolis of this byzantine set and it still does not look that filled up.
Moreover i always tried to convince Ogedei (when he was still making sets that is; but then again he only made asian ones) to agree on some conventions, such as a common centerpiece, or common basic building sizes, but this did not happen. Furthermore when RedAlert left it was obvious that there would be no scene here for city making anymore. Mrtn has created some impressive sets, which had their own style and were close to Firaxis (although imo a lot better) but again he could not help with setting a convention since he did not create the gfx himself (so he could not conform to graphic making he did not control in such a manner).