[Suggestion] Taxes?
I couldn't find this being discussed in any of the suggestion threads but I think taxes would be a good incorporation into the game's economy. It could be used as an alternative to gold mining in cases where gold mines are not available/you need more income to sustain your empire (or kingdom :p)
It wouldn't have the incorporate the tried and true more taxes=higher unrest formula that all 4x's seem to follow. It could be a multiplier on population growth as sort of an anti-prestige (more taxes=less people want to move into your cities).
I'm currently playing a game that seems to have a distinct lack of gold mines. I'm in the late game, all my "discover awesome resource" technologies have been researched, and I'm having problems raising the gilder necessary to even have a decent army. I'm resorting to roaming around killing creeps for the gildar.