Hearthpwn

Differences between this list and standard Quest Priest (https://www.vicioussyndicate.com/deck-library/priest-decks/quest-priest/standard-quest-priest/):

+2 Mind Blast - Alexstrasza into Mind Blast + Voidform is your main win condition. Even against druid, you can maintain enough of board control to destroy their armor with creatures and finish with burst.

+2 Twilight Acolyte - great removal and threat. 

+1 Temporus - at last, it found a place to shine, in Quest Priest where you have a lots of life to survive opponent's 2 turns. Turn 1 Alexstrasza into turn 2 Mind Blasts/Voidform kills almost everyone. Especially these Big Mages (after you take care of their armor). And it's a Dragon for every synergy.

+1 Mass Dispel - great utility card, silence and draw.

-2 Spirit Lash - too unimportant, you have enough mass removal against Paladin, and it's so bad against everything else.

-2 Rotten Applebaum - too weak, you have Amara, Warden of Hope for healing and you get her usually fast enough. Sadly, it appears no Witchwood card is good enough to make the cut instead.

-1 Shadow Word: Death - it is useful sometimes, but makes it more difficult to find with Shadow Visions the most important spells (Mind Blasts). 

-1 Archbishop Benedictus - good against King Togwaggle, but it's not enough. Many times he will sit in your hand doing nothing, as either he's too late, or you don't want to use his ability as it may even weaken your deck. And going fatigue when you play Mind Blast is not your win condition.

Early game you play the same as standard Quest Priest - deathrattles, removal, trying to fend off early aggression and complete quest. Use Shadow Visions to collect additional Mind Blasts if possible. Late game, you either try to get board control and finish your opponent with creatures, or burst them with Temporus/Alex/Voidform/Mind Blast.