I hear you.
Limiting the size of treasury doesn't work well, because it needs to be very large to enlarge the temples after a while. And while I originally thought those prices were just insane for the higher-up levels, every world in the game has a couple huge temples.
But I understand that a constant money drain is not much fun. Still, I want to tax temples, to make them not banks and also to keep money moving around. But I hear you. So here are two ideas to solve the issues:
a) change the tax amounts - half taxes for guilds, and quarter taxes for temples. I could also add a "tax free" minimum amount, maybe 10-50 gold per size. That would give the temple some amount to cover regular expenses with that is not taxed.
b) change the tax type - I could store the amount of gold put into the treasury between tax days, and tax only that, i.e. turn it into an income tax. This would also reduce the lord = massive balance problem a little, but it would reduce income through guildhouses dramatically.
What if you taxed gold as it was placed or removed from the temple? Then you don't need to store the amounts since the last tax day. I guess the problem here would be trying to place certain amounts of gold in an account for the taxes, but with the proper UI that should be handled pretty easy.
