I feel like becoming a priest and then instantly joining an enemy realm to begin griefing the realm where the religion is dominant, in an RPed way of course, just to show how stupid this restriction is.
Because if "roleplaying" is the solution to this, then "roleplaying" should *also* be the solution to spies who join realm and annoy realm mates. Why do realms get a ban function?
I have personally been griefed in the past by people joining my religion to get temple locations, and I know of others who have been griefed by people joining the religion to spam. Had the griefers known they could become priests for unlimited griefing powers, who knows how much they would have ruined the fun of everyone else. And they can easily RP justify their actions without making it any less harmful to everyone's gaming experience.
If you want kicking priests out to be tied with schisms, then code the kicking priests out part *now*, and add the schisms whenever. Religions aren't broken without schisms, but they are without being able to kick out priests. Cause a minor follower loss if you think it's so important, but always remember that there *are* griefers in the game, and they often RP to weasel themselves around the rules.