I'm thinking of moving away from the very AoE style house building population limits that are in the game at the moment. Instead the palyer will be able to invest in "Civilian Buildings" which will promote growth of the town. Civilian buildings may be erected by civilians of their own accord as well. If the population goes over the number of buildings, there will be penalties in the form of increased squalor (leading to plague), more poor people, less economic prosperity and more unrest.
In addition fires will become a risk, which militia can help to control. Militia I am thinking of changing so they cost 1gp to recruit rather than being free but are downed to a 4gp salary, the same theoretical pre-tax income as a citizen under average prosperity.
Thoughts?