Wrong. So many people spouting bull 
in this thread qhen they obviously have zero idea WTF they are spewing.
When experienced players Shaman tank and put in the effort, it shines tenfold. Shamans can fully tank 5mans, 10mans, off-tank & main-tank raids. But, this is reliant on personal and guild experience. Our overall defensive statistics won’t reach a warrior’s. However, it isn’t necessary to do so, to tank.
Can shaman’s tank WotLK? Let’s ask one who actually knows the aanswer and actually posted the answer here.