Hearthpwn

Dragon priest has lost quite a lot with the latest expansion, but is still quite fearsome.

Still tinkering with it of couse, but I've found Wyrmguard to be not bad at all in an OTK shell. The deck is full with high-health minions, and it's quite easy to go for a huge attack. We also have a big amount of taunts and area damage effects, so aggro is usually not an issue. If we want more late game value, we could probably add Ysera too, which is very good for the combo as well.

Just a quick overview of main choices:

Big Health Minions: Tar Creeper / Twilight Drake / Wyrmguard / Primordial Drake: these are the prime candidates for the OTK, but sometime a few power word shield can make other minions good targets as well

AoE Effects: Duskbreaker / Primordial Drake do the job of keeping aggro at bay very well

Draw/Tutor: shadow visions is best kept until later, when we know for sure which part of the combo we are missing, but sometimes we may as well need to look for a shield to cycle. Novice Engineers are there for cycling too.. they used to be two Faerie Dragon for early game, but the cycling is more useful, and there are enough dragons already

Some peculiar choices:

Crazed Alchemist: mainly an alternative Inner Fire for OTK, but can be quite useful for other tricks, especially together with Twilight Acolyte or any high-health minion. I can also be used to soften up enemy taunt minions, like turninga voidlord into a 9/3 for easier trading (bonus if you also steal the 9-attack with the Twilight Acolyte!). You can do it the other way around too: first you Acolyte a big X/X minion, give him a 2 attack, then swap the 2 to health with the Alchemist for an easy trade.

Cobalt Scalebane: with the huge amount of taunts we run, this dragon can deliver a lot of value. It's important that we can win also outside of the OTK path, and this is very useful in this regard

Wyrmguard: at first look it seems underwhelming, but a 4/11 taunt isn't that bad after all, and it's especially very good for OTK and to defend cards like Cleric and Scalebane. The 4-Attack also makes it incredibly durable against other priests

I'm thinking about other possible variations, in particular:

Lady in White: she may indeed make cards like Wyrmguard, Primordial Drake and Tar Creeper (and even Ysera in case) extremely powerful, but it has bad synergy with Twilight Drake and Twilight Acolyte, which are both very good. Losing Twilight Drake in particular would weaken the deck both for the OTK and the Dragon Synergy. Still worth a try for sure anyway

Nightscale Matriarch: with no circle of healing or Divine Hymn I'm not totally sold on this.. it's still a big health dragon with a nice ability however.. she could be worth a shot, of course in the Wyrmguard slot.