yeah thats why I was thinking you could use the barter system instead, as I suggested. I dont know if this is too hard, or you are already too much in the midst of modding, but I had several ideas for that. Im certain you could have come across these before:
- Dont make houses generate coins (until stage III).
- Have what i call 'nobility buildings'. These include the apadana for the persians and prytaneion for athenians. These should generate gold, at a moderately high rate. (Also depending on where they are situated). It should be 0-2 coins/second. These buildings get +1 coin for each temple or farmland they are near to, but caps are +2 coins/second. This historically was the case in many civilizations.
- The market building doesnt generate coins itself, but each time a trader gets from one point to another, the trader 'pays' 1 coin. There should also be a minimum distance between two markets (or two dockyards, a market and a dockyard). This is true historically, as a country receives import taxes.
- The temples generate gold. The amount depending on how far away they are from the houses. For each house close to a temple, you could generate 1 gold/second. There should also be costs to running the temples. Therefore, you could have the rule that temples generate -2 coins/second, and therefore, to make them profitable, have to be build near houses. These cap at 1 coin/second. This is true historically.
- In the final (third) phase, have taxation technologies that in each level you could get 0.1, 0.25, 0.5 gold per house. However, this would mean for the non-champion units, they would receive a -25%, -50%, and -75% loss to health and gather rates. Sure this is harsh on the workers, but eventually, this is would create the specialization we see in high tier nations/ societies. Also as you tax more the people, the lesser their living conditions (obviously).
I hope this helps.