I would love to see a way to de- and re-priest with maybe a hefty cooldown, or a faith penalty instead of complete reset.
Problem is that being a priest in PvP combat has only upsides, no downsides at all and is almost a requirement to be viable. I love seeing my main's numbers go up, but having to choose one path or another... or level another character. I dislike it.
Maybe only non-priests being able to become champions and only gaining a set amount of faith, maybe even restricting the spell pool to PvP ones.
That way, you can level up channeling as a priest for a while, yet decide to go back to being able to do everything else, while having a choice to quickly priest up again solely for PvP