The Malygos version with 2 Inner Rage's + Whirlwind takes + 1 cardspot from deck, in total 6 combo pieces. Kael'thas takes only 5 AND is more flexible because you can succeed on the combo various ways!
Deck beats easily any slower meta deck such as Priest and mage. Big Druid is about 50/50 depending on their aggressivines. Rogue is 60/40. Aggro decks have the advantage, but this deck surely can put up a fight because of the massive armor gain!
Here is couple recordings of games so u can see how it's done:
Game againts Thijs, mirror match: