I just thought was I was playing c2c that achievements could be a possibility. I often try to break records with the amount of hammers or happiness in cities as well as the city size. So my idea was that once you get to a certain city size or hammer amount you get a money/gold reword which is higher if you complete a better achievement. Here are some examples:
Village: city size 5, reward: 500 gold
Town: city size 10, reward: 2,500 gold
City: city size 20, reward: 10,000 gold
Obviously you could have achievements for any countable value in the game but I won't suggest more unless you like the idea...
Village: city size 5, reward: 500 gold
Town: city size 10, reward: 2,500 gold
City: city size 20, reward: 10,000 gold
Obviously you could have achievements for any countable value in the game but I won't suggest more unless you like the idea...