Please don't listen to the poster above me about salvation.
The day I'll be out healed by a 31 pt heal sorc/sage I might agree with you. Reasons for not taking the top ability in the sorc/sage heal trees:
1. You will be sacrificing bubble stun and force regenerative abilties in the lightning tree. That alone is reason enough to not take it.
2. It has a high force cost and if you're focused you'll never be able to channel it.
3. It requires that people stack (read: a smasher's wet dream)
4. Let's say that you have six on a node, a maximum of three will take advantage of it due to the others being spread out.
5. Mobility, even those who it was intended for will move around and most likely miss out on a few ticks.