I wonder if changing SoS effect to be more piety dependent would be a good idea. For instance, for Xs your natural mana regen is increased by X% (I really have no idea what would be reasonable numbers because I don't play WHM). This way, the more piety you stack, the more mp you get back which scales along with how much mp you have overall. It will also make piety a more attractive stat for WHMs since they get bigger mana pools + bigger mana regens.
