I think it would be nice to have the amount of income per turn shown beside your total gold amount. For example: gold: 300 (+200) the +200 would be your gold earned per turn.
To be fair, you can actually track your income from the overview screen, but it certainly would be nice to have it readily available so you'll know if you'd be able to spend money on buying a cheaper unit and still have enough to get an expensive one next turn.
