Well, this is more flexible than Polymorph because you can use this on your own minion to trade or go face. The downside is of course if you can't deal 2 damage, somewhere in the universe, Rexxar is happy.
Aggro mage comeback? This card allows you to take out things like giants or really sticky high value minions while also allowing you to push for damage by transforming your own minion possibly allowing for lethal. Really interesting card.