Really tough to imagine a world where this is good. If you put it on a poisonous minion, then why not use Deadly Shot instead? Would you play a "1 mana +1/+1, give your minion Rush" in Hunter? I don't think I would. I guess it can be used to activate Overkill, but it doesn't seem like Hunter has too many valuable overkill minions. Activating one Oondasta doesn't cut it.
I voted "playable" but I think this card has a lot of untapped potential that people may begin to unlock once the expansion comes out. This is one of those cards like "Play Dead" that need to be played with in order to really get a feel for.
The effect of this card is not good enough to warrant a slot on your deck but actually the biggest problem with this card is that it is 1 cost, Hunter has a lot of good cheap cards which make this even worse
Just out of curiosity, what do you think would happen if this was played on a Giant Sand Worm played in the same turn? It would attack an enemy minion (and probably kill it), but would it be able to continue attacking according to it's ability?
I am also curious about this interaction. Giant sand worm + this + beastial wrath = full board clear?