The one thing I pulled from this is a new idea for a tanking mechanism, based on your 'Conversion' skill.

Right now Paladin has Shield Oath and Warrior has Defiance to make them 'tankier', with one mitigating damage and the other increasing HP and potency of healing received. Maybe another tanking mechanic can be a buff/toggle that pushes damage taken towards the MP pool first, with damage consumed by MP being reduced by say 50%. It would be encourage this tank class to put points into Piety, instead of Vitality, and would also lead to different strategic decisions based on any skills that required MP and the fact that healers can't replenish lost MP.

Just a thought.