Ah, seems like BBeast had a similar idea to me.

While brooding over Holy Sites as a structure like Ilu, Tek, Jvan and others use, I came up with another proto-idea. What if there were two types of Holy Site? One that gives might (temples for worshipers and such) and one that gives free actions / 0 might actions, so say, as the god of plants, you would always need to spend might creating plants (unlike the current system where plant creation can be justified as a free action if you have the plants domain) unless you spend some might creating the Gardens of Somewheria which would give you the free actions.