I like it as a card, I feel it could fit into some unupped decks, but it's not EXTREMELY powerful. Because of the no-fractal thing I think it needs a very minor buff, maybe have it stack onto the attack, but then reset post combat.
So it would get the 2+1(ambush) and then attack with that amount + ambush. But only have it stack for a turn otherwise it goes berserk. I feel like this is better, but could even up it's cost 1 for the unupped version.