Hearthpwn

explanation:

so, this will be my first take on combo priest. In standard priest got almost no toys supporting viable archetypes - at least in my opinion - but two cards that can make a significant impact in wild: Mirage Caller and Shadow Visions.

Mirage Caller with Emperor Thaurissan on a full hand is insane, as it enables you to play all your combo pieces in one turn. ideally this would be Prophet Velen,Mirage Caller on velen, 2x Mind Blast, Auchenai Soulpriest and 2xFlash Heal.

that's 80 damage in one turn on 8 mana. but for the combo to work, you'll only need one discount on velen, mirage caller and your mind blasts: 4 card combo for 40 damage.

as Shadow Visions discovers a spell out of your deck, it does two things in this deck: it can double as removal, aoe, damage or even carddraw - with a little bit of luck the one you need - and it makes your deck less draw dependant because of its high flexibilty.

Mirage Caller is also very flexible. in a tight spot it can make a copy of Priest of the Feast to produce some huge heal, it can double up thalnos for early board removal, but of course you will want to copy velen and thaurissan.

I'm not quite sure how much board clear or removal will be needed, so I might swap holy nova out for heavier removal later. 

strategy:

stall while drawing your deck, drop thaurissan and mirage caller or mirage caller and velen after thaurissan discount and burn 'em with holy... mind blasts...