Hearthpwn

Today I theory crafted what will be a meta-defining new Priest deck, I should think. Let's go through the cards and synergies:

Shifter Zerus

This card is remarkable in that it can transform into other class cards. Enough said.

Confuse

This card completely sums up the way Anduin feels about the cards he's been getting, and is thus integral to the deck.

Convert

Since other classes get better cards, this should be an auto-include in every Priest deck. Don't keep this in your starting hand in the mirror; this should be a rare occurrence so don't worry about it too much.

Pompous Thespian

Maybe this is the 2-drop Priest needed?

Purify

The most exciting card of the set. Its purpose will become clear later.

Moroes

Very exciting new legendary. I know, I know, the 1 health stat line is troubling, but Priest has a number of cards that can buff it up.

Power Word: Tentacles

Moroes isn't going to be long for this life if you keep him at 1 hp. Quickly, engulf him in tentacles VoHiYo

Angry Chicken

Two copies of Power Word: Tentacles, only one Moroes... this should do.

Mindgames

A 4 mana 7/7 most of the time, overload free.

Violet Illusionist

This must be a mistake, you're probably thinking. Oh no, it's very much intentional. Not only do we have access to a weapon, Atiesh from Medivh, the Guardian (you might as well attack with Atiesh right away because it's getting oozed instantly), but we have a couple of cards that present an unfortunate anti-synergy: Priest of the Feast and Auchenai Soulpriest. If Purify isn't at hand to silence off that pesky Auchenai, just throw down the Illusionist to negate that self-harming face damage.

Power Word: Glory

We've got purify, and Power Word: Shield seemed a bit overkill at that point, so I've gone ahead and thrown this little gem into the deck. You'll thank me later.

Shadow Word: Horror

Indispensable in this meta, really.

Holy Nova

One of the only good cards in the list One of the best cards in the list!

Medivh, the Guardian

This looks promising.

The Boogeymonster

Great synergy with the Priest hero power.

Icehowl

And here we have it, the main event, the reason Purify is so unbelievably OP, this card right here. Ten damage to face! SMOrc