Hearthpwn

I love dragons and the Dragon Priest and when Standard arrived with Deathwing, Dragonlord, I was sure that the Dragon Priest will be stronger. I removed my Wild cards and added a few new. It worked out pretty well.

Mulligans

You should mulligan for early game. Never discard 5 or less mana dragons as they will be good activators while not dead for a long time. Sometimes you may want to keep the shadow words in hand.

Replacements

The most flexible card is the Twilight Drake. I find my hand with more than 4 cards at any time so 4/5 is the least stats you can get out of it. This minion survives most board clears so it forces your opponent to use hard removal. However it can be replaced with Twilight Guardian if you struggle a lot against zoo and aggro decks.

Ysera is a great late game card in any control deck. If you don't have her, I Highly recommend you to craft her, but a temporary replacement can be Nefarian.

I find Deathwing a good activator and great comeback mechanic. He can be replaced with his twin, Deathwing, Dragonlord.

Shadow Word: Horror is great against zoos, except Shaman with Flametongue Totem, but if you hate Darkshire Councilman, you can add a second Shadow Word: Pain.