While Shroud doesn't scale as well as Aether it's not certain what kind of traits whm will get later on. Increase refresh to 200 etc.

Right now though Whm and Sch are pretty balanced because of their potency per MP on heals. Even Aldo if it crits would only be 900 potency for over 300 MP. Regen is always 1050 potency for a little over 200 MP.