Hearthpwn

Ever feel like this game needs more phoenix? ...PERFECT!

The core of this deck is the basic stall and spell package. 

Sandbinder pulls Pyros consistently (also the reason we don't run any other elementals despite having Frost Lich Jaina)

Turn 6 is the earliest you should play your Pyros, and only with a Molten Reflection. 

Turn 7 play Pyros1 and Carnivorous Cube it. If the cube gets silenced/morphed it isn't the end of the world since you have a copy of Pyros2 already in your hand. Be careful with Pyros1, if it gets poly'd or stolen thats your game plan over. Same if Pyros1 AND the Cube that eats it get silenced.

Turn 8 you can play double Molten Reflection on either the Carnivorous Cube (the new cube WILL have the stored Pyros) or one of the Pyros2. Its next to impossible for someone to clear the entire cube and its contents in one turn.

Turn 9 you can do the Spiritsinger Umbra/Cube or Cube/Reflection combo in the same turn. 

Turn 10+ you just start slamming down Pyros3, who have lifesteal once DK Jaina is active. You put down so many big threats your opponents can't keep up with all the silence and kill spells. 

Substitutions

Pyros is the only legendary thats truly mandatory, although the Cubelock Matchup becomes nearly impossible without Frost Lich Jaina

Cairne Bloodhoof is your backup copy bait, and should probably be replaced with something else that fills that role. The Lich King, Splitting Festeroot/Violet Wurm, or even Rotten Applebaum

Spiritsinger Umbra is a very powerful tool, completely broken synergy with Carnivorous Cube).

Faceless Manipulator, Zola the Gorgon, and Prince Taldaram (with a few changes) are also good additions, but you don't want to commit too hard to the gimmick or the deck just falls over in most games. 

 For Taldaram, swap Arc Int, Counterspell, and Stonehill/Tar for  Primordial Glyph, Arcane Keysmith, and Saronite Chain Gang 

Matchups

This deck can struggle against Baku Hunter. You just can't compete with that hero power, unless you get a TOTAL stranglehold on the game and play DK Jaina on curve. 

Stonehill Defender and Witchwood Grizzly will sit on any other aggro decks. Tar Creeper will interfere with Sandbinder pulls, but its not unthinkable to replace Stonehill with it

This deck is designed to fight Cubelock, since you stunt their Bloodreaver Gul'dan with Polymorph and do a fairly decent job of matching their value and (with DK Jaina) sustain. If they don't instakill their Cube (i.e. they're noobs) a Poly or Spellbreaker can totally crush their dreams. Counterspell puts in work against them too, giving you that window by countering their Dark Pact, or saving a Pyros3 from a Siphon Soul, which can put up to 20 distance between your lifetotals. 

Against Shudderwock OTK you need to be proactive, while also being mindful of enemy Hexes. Its not a GOOD matchup but its not unwinnable. 

Flamestrike is better than Blizzard for countering Dudedin decks, but Blizzard is better against... everything else.