I have always felt that if a creature taps into the weave (Uses Magic) it should have fewer hit points than somone who doesn't. Therefore the Cleric should have the d6 hit die and the Rogue should have the d8. Even if it is a divine magic clerics spend more time in books. Rogues have grown up on the streets which is tougher. You are in danger of making the classes unbalanced. I have heard so much from other players that state that the cleric has always been more powerful than all the other classes. This will off set that a little bit.