A few suggestions:
1. In the build list, display possible buildings on the left and city stats on the right. When a building is selected, turn city stats red or green (for decreases or increases) and indicate the change (i.e., city stat A was 24, the building will make it 22; display in red 22 (-2) or 24 - 2).
2. Card graphics should be informative. While very pretty, a playing card motif devotes two thirds to three quarters of the card real estate to a picture. That picture should convey information while still being decorative. That is, you should have a pretty good idea of what the unit / building is or does from the picture, and the functionality of the unit / building should be close to what one would expect. Again, most players have certain expectations for wheat fields, scouts, heavy armor, etcetera. It would be helpful if one could navigate readily by the pictures. If the pictures aren't intuitive, then they should be ditched because they take up too much real estate and would be providing misleading information.
3. There should be ready access to basic economic statistics, and the ability to quickly drill down to see all of the components. I.e., my growth rate stinks. Why is that? Ah, it's because I've got a food shortage. How do I add more food? Here's a list of all possible ways to get food. Which ones am I weak in? Or, why don't I have enough gold? Here's a list of all the sources of gold you could have and what you're spending it on. Note that the list should include all POSSIBLE sources, even if the value is zero. That tells the player how they could improve. For example, gold could come from trade, mines and taxes. Maybe the player doesn't have any mines. Maybe the player doesn't realize that they could have mines. So you want to put mines in the list with a zero value. Then the player could look at it and say, ah! I could go out and build mines!
4. When deploying a building, there should be some indication as to what effects the terrain has. Currently, there are legal and illegal building tiles displayed, but presumably at some point you'll be able to put a building in different places, some of which will offer bonuses. The effects of placing a building in a particular place should be clear.
5. Does it matter where and how you deploy the buildings? Right now I can't tell. Can I just build randomly, plopping buildings down any which way? How do potential borders change? Can I, or should I, stretch a city in a particular direction to reach some distant resource? In a game where the city grid is predetermined, this is less relevant, but where the city grid goes directly onto the game map, and can change based on your building, then there should be some guidance as to the effects of building on the city's dimensions and functionality.
