Well, I'm officially jealous of mages for the first time ever. I love the whole steampunk aesthetic. And now here you guys come along with gears on your shoulders. GEARS! I want gears! Also, I think I've figured out the theme of this tier:
All the "big players" in the Deathwing story, which includes:
The 5 Aspects (we've seen 2 so far)
Thrall (shaman gear instantly made me think of him)
The faceless ones (Warlock)
The Twilights Hammer cult
The Druidic factions (Avengers of Hyjal, Malfurion and his friends, hence the very basic "druidic" theme of the Druid set)
And possibly the Shadow Wardens (Rogue gear maybe?)