At the moment nothing is stopping clerics / mages, what we need is a counter to them which is the void knights mana drain prior to 1.1 patch.
This is the only skill that will balance this 2 classes, not a nerf, but a counter. In that way PVE is not touch.
Trion you can see all the request in forums, this a counter is very needed for 1.2 patch.
Void Knight mana drain buff is the answer.