Have you looked at the warrior talent trees at all???
Blood and Thunder
Rank 1-2 When you Thunder Clap a target affected by your Rend, you have a [50%/100%] chance to affect every target with Rend.
Thunderstruck
Rank 1-2 Your Thunder Clap leaves a zone of energy on the ground for [5/10] sec, dealing 0 damage every 0 seconds to enemies that cross it.
Warriors are getting consecrate and aoe bleeds. I think saying they aren't viable aoe tanks is pretty absurd. Also, you need to remember that aoe tank should be less necessary come cataclysm as CCing mobs will be back.