3/6 is pretty much optimal for a reactive 4 drop like this one, a huge help against Zoo if you draw Holy Nova, but otherwise it's simply never going to do enough on it's own. Priest will be decent after this expansion, but honestly at this point it seems the only way to save them is to bring back Dark Cultist, or something similar
EDIT: also in arena a 3/6 is pretty ridiculous, so maybe priest will become a playable arena class, although you'll still want Velen's, if you manage to play this followed by Velen's Chosen you pretty much win the game
This is deceptively strong. It's got excellent stats for a 4-drop, it has pseudo taunt against aggro/tempo, and it can heal you like crazy later on if needed. I would definitely consider running this along with Shifting Shade as my 4-drops in a N'Zoth deck.
If you don't kill this card or the Priest the turn after this card comes down as an aggro deck you probably just lose. This card is a soft taunt that can act as a massive proactive heal in the late game. This card would fit perfectly into StrifeCro's Yogg Priest :)