I think this will be good in NZoth decks because a 3/4 and a 1/1 isn't really terrible value for 4 mana even if the 1/1 is vanilla, yet if it has a death rattle it's nuts. You can't really run it with doomsayers, which is a problem.
This card is nuts...no idea why people are sleeping on this one. Put it in a deathrattle deck and if you pull any relevant deathrattle minion, you get a massive tempo gain. Heck, deathrattle hunter seems like a great starting point.
The statline really isn't that bad - I imagine just throwing him into a deck that has 5 or 6 good outcomes. If he fizzles, his statline is still fine. If he pulls something good, he can be just ridiculous. In my current deck Sylvanas, Rag, pillager, xaril, or even huckster are great outcomes. You're not building your whole deck around him, you're just throwing him in because the downside is small and the upside is huge.
He reminds me a little bit of Totemic in that the "bad" outcomes are fine while the "good" outcomes can literally be game winning. I think he's going to be better than most think, and great in control decks as a low risk way to get some early momentum.