rated as bad. Seems weak stats for 8 mana. Almost need to pair it with Baneful Banker , Cornered Sentry or Gravelsnout Knight to ensure some value from it by giving you another one or a guaranteed kill at turn 9+
This is actually pretty awesome IMO, if any form of control warrior can make it to tier 2+ (personally I've had success on ladder with a control shell that includes the rush package, plus Dr Boom and Omega Assembly, as well as Dead Man's Hand to break the control deadlock). If we consider a 5/5 buff on a minion to be worth about 3-4 mana (by Blessing of Kings standard it's worth 5, but people don't play cards just because they're 'fair'), then we're looking at a ~4/5 rush for 5 (technically 5/5 but as you badly want to Overkill it realistically is only doing 4 damage worth) that draws you another rush card + the imaginary buff card.
Not to mention, the rush package (the 3 mana Worgen, 4 mana temporary 5/5 and Crowley) can struggle against bigger threats, and the buff definitely helps there - even if it hits the Worgen that's an 8/8 rusher. Hit Crowley, and he can hit something big to start growing, as opposed to having to start with a something much smaller.
Stats are too low imo. You need to kill something with 4 HP to get the effect to go off, and by turn 8 if you're playing against Control, then that's hard to do and against Aggro this card is hardly something you'll be able to do that late in the game.