I do like, at minimum, the idea of priests holding the equivalent of lordship over a temple, or the equivalent of ducalship over several temples. It offers more for a priest character to aspire to within a religion. Allowing such priests to 'change loyalty' of temples, obviously with cost, is a nice way to add to schisms, though I'd leave it as an option for more than just schisms (at a higher cost, depending upon stance between faiths switching to and from).
As for the coding though, it would seem to be an intensive effort to implement.
