We really need a building that provides a certain amount of gold based on the number of people in the city, like a tax office.  I don't mean a set amount for the building, but one that generates a changing amount based on the population.  Right now I look at the masses and all they are good for is recruitment, which gets replenished fairly fast in high level cities.  Something like providing 1 gildar per 100 people would be good, making it only worthwhile at high level cities and make those people pay for being protected!