Originally posted by therussian91

You forget about the huge drop in loyalty across your lands, and the higher chance of rebellion.
Provinces in vanilla are generally designated with rebelliousness "0". Now if you turn this 0 to a 2 you'll find out that disobeying the Pope is a rather... bad decision - rebellions from Catholic subjects in your own lands due to the excommunication of your king/emperor are ferocious and frequent. In vanilla however this is much less felt.

Many Thanks

Noir