Mulligans
Replace the three 10 mana minions with Cthun, Nzoth and Yogg.
Winning move vs control: Nzoth, which can summon Deathwing, Siamat, and 2 Taunt. If not clear, next turn Alex and win. If cleared, next turn Alex on an empty board. Then Cthun, your opponent will die 95% the time with only 15 hp and have to clear your 8/8 the previous turn.
Vargoth is vital in the deck because it can combo with a lot of spell. Note with Reaper , you can draw 4 card for 1 mana while doing 4 AOE with Vargoth. Other combos : Vargoth + Shieldblock = draw 2 gain 10 armor, Vargoth + 5 mana cthun spell = insane swing.
Finally , if everything fail, you can always pray Yogg. You can cast nearly 20 spell with this deck