You're under the mindset that Gladiator warriors will be able to tank, which is not the intent. Elemental shamans use a shield too, it doesn't mean they can tank.
- - - Updated - - -
Sorry about that, I didn't check the date. But still, you shouldn't take such a hard stance (hehe) on things so early in development. You're probably right that it won't be optimal for hardcore raiding, but fuck it; why can't it? They may design it stupidly OP at first.