Hearthpwn

In this time, when everyone is experimenting with new (and often garbage) archetypes, you can climb pretty easily with old reliable deck, slightly upgraded with new cards.

Against slower decks, you can go for more aggro approach, producing our big bodies as soon as possible, going for face with weapon and so on. Against aggro, be more thoughtful, clear, keep your health high, and then finish them with big value legendaries.

Plague package:
Plagues are now significantly buffed, since there is now no Steamcleaner in the card pool. The rainbow deck allows us only to use Helya and Down with the Ship , but its well enough to stop any highlander shenanigans and to generally put more pressure on opponent.

Corpse package:
Ton of corpse generation via Mining Casualties , Crop Rotation and general play will allow us to put more pressure with our big bodies Corpse Bride , Stitched Giant , and bringing us close to go for a nuclear Climactic Necrotic Explosion. 

Climactic Necrotic Explosion Is not our main objective, as there were OTK decks for this in the past. With rotation of Malignant Horror, you will not be able to do 30dmg explosion. Just make it big and juicy, and then use it for best value.

Big Value stuff:
The Primus, Reska, the Pit Boss : No explanation needed, just OP.

Climactic Necrotic Explosion , as of above.

The Headless Horseman Really great card, once you have the upgraded hero power. 3dmg hero power is good enough to be played at turn 6 just for board clear, or aggroing face with that hero power. As soon as you have the head, the value is incredible. Discovering stuff like Gnome Muncher, Soulstealer, Cage Head every turn can win you game on its own.
The Sharp-Eyed Seeker is here just to draw you the Head, once you play the hero.

Notable cards:

Maw and Paw Not completely necessary, only legenary i would deem replacable. Play it when not much is happening, and you dont mind losing a bit of tempo. Even if they kill it right away (when often using valuable removal, because overestimating threat of this card), +5corpses are just fine if you can follow with Corpse Bride or Corpse Farm next turn to form big bodies. If they dont kill it, then extra health is always nice and our Climactic Necrotic Explosion is growing and growing.

Threads of Despair Really underrated card. Against low hp boards, is is ful lclear with just your HP ghoul. For big enemy boards, pair it with Crop Rotation. 

Crop Rotation. Very versatile card. You can use it on its own for corpses and clearing aggro trash, or pair it with a) Threads of Despair for big wave clear, b) Sickly Grimewalker for big targetsclear, c) Acolyte of Death for juicy card draw.

Rainbow Seamstress 3cost 3/3 with lifesteal, rush, and reborn? to good not to play that

Quartzite Crusher. Board clearing weapon with lifesteal, if you are controlling. 9dmg to the face, if you are aggroing.

Edit:
Took out Miracle Salesman, as it sabotaged the Sharp-Eyed Seeker. Inserted Zola the Gorgon, for its many uses, the easy ones being copying 0cost giant or Reska.
Other options are another copy of Threads of Despair, or Dryscale Deputy