So basicly i have been tanking heroics and Naxx, and i have trouble keeping Aggro on multiple mobs even though i am using any AoE i can like thunderclap, shockwave, demo shout, cleave etc. I have no problem tanking bosses most of the time but its just picking up and keeping threat AoE tanking multiple mobs.
well i guess its a combination of warrior AoE tanking being pretty weak, and your gear beeing abit low aswell (not like you are doing anything wrong with it, its just not that high level)
As you said for AoE tanking its usually: charge>TC>shockwave after that go for your normal rotation while tabbing and use TC, shockwave and cleave as much as possible.
Edit: oh and change your charge major glyph for the blocking one. Wont be that big a boost for AoE tanking, but it is considdered pretty mandatory for any warrior tank.