On average, Acolyte of Pain will draw more cards than a Novice Engineer. That said, it needs to be considered that he costs more and is harder to cash in. He doesn't net you a card immediately after he's played and is an excellent Silence target. Acolyte of Pain should ideally be played early game where he can hope to draw two cards. The catch, however, is that spending three mana on a one Attack minion is not what you want to be doing early game. Acolyte of Pain sits in an awkward spot, therefore, where you will need him to draw you into a strong late game since he will set you behind. It should also be mentioned that he is harder to activate than in Constructed: unless, of course, you are playing Mage.