I got to play some Cataclysm decks early in Hearthstone's Theorycrafting event, and Mage with Archmage Kalec was able to burn through a lot of opponents.
Deck List: AAECAf0EAv2eBIi+Bw6F5gazhwfHhwf0kQfopQeLsQfWvAfXwweGxAeSxAebxAesxgeT2geG4AcAAA==
Power Level Estimate: It's way too early to know, but this deck felt like it had some serious potential, with both decent tempo swings and lots of lethality.
Video Chapters
0:00 Deck Introduction
1:57 Deck Gameplay
--
Deck Spotlight | Hearthstone | ...oh no... spell damage spam is SCARY.