Remember there are a lot of children playing Hearthstone. And kids get frustrated easily. Heck, I get frustrated easily for an adult. But at least I can tolerate loosing a HS game, even by miles. Thing is, by adding the thief cards, a Priest with advantage on the board transfers this advantage into card advantage, and their healing combined with the additional cards means they succeed in the long run.

But that is how the class should work.