Sometimes, I wish I could do a little adjustment to my faith, but the way the game works, we need to create a new one. Every time I want to change the attitude of my religion on certain topics, I have to make a grand schism.

My proposition is to allow heads of faith (and only heads of faith) to do a little change (going from righteous to pluralist, from shunning witchcraft to making it criminal, etc.) once at a time, at the cost of piety and fervor.

If we really want a deep rework, we could also play around a mechanic similar to the way we need approval of our powerful vassals to change a law in our kingdom. There could be a system of "influential preachers" or something like that. They could be powerful bishop-like rank characters for a spiritual clergy and various rulers with high devotion level for a lay clergy.

I think it would be interesting to see how the pope would do minor tweaks over time. (Maybe the devs could program him to enact certain changes at historically accurate times/in historically appropriate contexts.) And it would be cool that your paragon of virtue, head of faith, ruler who spent his life studying theology and loved by everyone can, at some point, declare that it's not the end of the world if people don't need to ask permission to divorce or that kinslaying shouldn't be tolerated as much.

I think it could be great for RP to have a head of faith ruler who got cheated on multiple times to change adultery from shunned to criminal. Or to have a lustful character who started to have eyes on hi niece to make theological arguments in favor of avunculate marriage. Maybe it could be empowering to have a bastard character rising from rag to riches then making bastards actual legitimate children.

And it would be a nice way to make the theology tree more useful because, right now, most people take it max. once per playthrough.