I'm liking the 'priests write scrolls' idea. If a cult or church could suddenly summon a horde of monsters on your doorstep for being an unbeliever, you'd get yo ass to church.
If you gave religions a weapon, they'd have much more reason to fight. It would take some balancing measures and some testing, but I can't think of anything better than using the clergy to manifest power through the written word.
EDIT: Someone more familiar with making feature requests want to post this (and other ideas) so we don't hijack the thread?
