Worst/Most annoying viable faction to play

[doctrellor]

as the Papacy?

I united Italy, took out Spain and N Africa areas, so I owned the Western & Central Med, mind you it aint a victory, but for the Pope, that is pretty good..:P

using XL (of course)

[Gimli]

I've never tried the Papacy... I'll have to try it ASAP!

Do you get excommed for fighting other Catholics?

[seireikhaan]

I've never tried the Papacy... I'll have to try it ASAP!

Do you get excommed for fighting other Catholics?

Nope, they get excommed if they ever attack any provinces which you control. This also includes if they attack a province that you took from them and have under seige. Rather nasty trick, playing the Papacy, imo.