This game is a great thing for Roleplay.
Me and my friends are playing as monks. Nice feature in the game would be some animations (even static) when a monk is praying, or meditating. Maybe some items like hoods for monks. Maybe even robes that specify their "rank" in the monk community.
Maybe even skill tree. Skills like Blessings (for different buffs like Luck, Armorsmithing, Weaponsmithing and so on), Skill when you could for example bless someone's else monument or claim, skill for increasing someone's else piety, skill for blessing for example farm to give someone a better quality crops. And those blessing only for other's people claim (not for the monks claim so they do not overuse in only their favour but they actually help others.
Maybe a buff when you are near the someone with Piety 100 so someone is feeling blessed and his health regeneration is bigger.
Basically extending the faith and religiouos features in this game will certanly add some spice and intresting new RP ways
Cheers and good job about the game so far!