Here's how to implement it:

-Conj/Thaum get it at level 10-20
-Can only be used by Conj/Thaum
-Switching to Conj/Thaum starts the cooldown of 1 minute before you can res someone
-Adding res to the action bar also starts the cooldown
-Death penalty is unchanged

This way, unless you ARE a conj/thaum, then you'd be better off having the person run back and start their weakness timer sooner rather than later.

Exp loss on death is completely unnecessary. Having to wait 2:30 before you can be useful again is more than punishment enough.