I think it will own in GvG. Coon's suicide and sheep's rift combo is awesome. Bunny can't break free from rift unlike other stuns.
I don't mind the damage. It's stronger than electro attack so that's pretty good.
With its ability to stop an attack from activating I think of it like a defensive skill
Kahru if you ever played a priest you would know Celestial does crap to most bosses after Skull. Trust me Pheonix alone is way faster.