Violet Teacher sees play in token decks where you can buff up the tokens or finish you opponent with them. Violet Teacher isn't good enough for Miracle Rogue even, who has much better cheap spell selection than priest. This is a bad card, not something priest needs.
Looks awful, and looks even worse when compared to vex crow.
1) The obvious comparison should be violet teacher 2) Violet teacher is a good card 2) This is arguably better than violet teacher.
Is token priest going to be a thing? I'd have to think on it. Extra Arms and Elixir don't really light the world on fire. And there's no board wide buff...but there wasn't in Oil Rogue either. Granted, cold blood is light years better than any of the current priest buffs.
I'd expect some level of miracle priest to be at least T3 just based on what we currently know.