fetching specific cards from your deck is very strong, it's basically cheating in card games...
bad otk decks aside, this card can be any other spell in your deck depending on the situation. How often priest player just need that one board clear or death or something to be in the game but not getting it. Priest is a class with very specific answers, they can't deal damage to stuff like others can and you need those answers at the right time. This card can add redundancy to your deck. The thing is you pretty much have to play this before you need the answer, likely a turn earlier to have the mana to cast the spell you get and that's fine. You should be able to cast death and this in one turn. You think you need dragonfire soon, better fetch it a turn before. It can fetch healing potion if you're dying, pyro this into circle of healing, draw bunch of cards and so on.
In value oriented games that go late, you can play Elise then get the pack with this card. it's pretty huge. I think it's good. I don't know if control priest is going to be a thing, but if it is then it will like this card very much.
