I imagine the Papacy being overhauled would effect to everyone (i.e muslim decadence may not be a part of christian nation play, but it still impacts the muslim nations regardless). Could be making Theocracies playable or something though.Great suggestion, but as the base title suggests, the game is supposed to be based around the Crusaders (Catholics) and this system is fairly well developed. If they did improve upon this, I would hope it would be in the form of a patch, not a DLC.
Time will tell, can't wait.