I don't know if you guys are taking suggestions this early in the development, and if not feel free to delete this. I think it would be a good idea to offer different types of cities other than the regular one that gives 100 gold per turn. While the regular cities would still be more prevalent, one or two of these special cities could be placed in the center of the map or at strategic locations to add more value to certain areas of the map. I'm suggesting two such cities. 1. A merchant city that gives 200 gold per turn but is very easy to neutralize and capture so that you have to defend it with your units if you want to keep it. 2. A stronghold that gives 0 gold per turn but is harder to neutralize. When a player controls this type of building it will be able to launch weak attacks a short distance away. I'm thinking a range of 2 or 3.