the AoE is tied to the card's battlecry so it only happens when you play it. the hero power is to create a zombie beast by stitching together 2 random beasts that cost 5 or less.
it's a slow card for sure and the 2 AoE and 5 armor are meant to help you versus aggro. but control hunter will need a few more tools to support this. like, way more good removal options. there's a reason why warrior, priest, mage and shaman have had the strongest control decks in the game.
I think the 5 cards they revealed are supposed to give us a representative sample of the set. they usually leave good card reveals until later. also it's impossible to tell what's actually good. everyone though hunter quest would break the game but it's one of the worst quests aside from warlock.