Armor

Priests may be limited in the types of armor they wear. Some sample limitations:

May not wear non-metal armor

May not wear metal armor

May not wear magical armor

May not wear any armor

May not use shields

May not use certain types of shields

May only wear armor made by priests of the same faith

Any of these restrictions could be made for any of the four reasons given above. If metal armor disrupts clerical magic, then it could not be worn by priests. If the religion's philosophy forbids harm to animals, then leather armor may be forbidden. And so on.

Armor restrictions don't just reflect the god's attributes or prohibitions; they help define the combat roles of priests in the campaign. A priest who can wear full metal armor is more likely to be a combat force in the campaign than one who can't.

You can be more sure that a player who picks a priest-type which is limited to less efficient armor is a player who wants to role-play a priest, rather than one who merely wants to play a fighting machine who is efficient in both combat and magic.