ok, you can use a warrior, but I am biased and hate them :P

the reason I bring a prot pally and a feral druid, is that the pally can MT all the bosses that only require a single tank, and the druid can DPS.

I have gotten a bear with 4 shamans, its definitely possible. Stacking shamans and chaining heroisms is a good way to beat bosses =)

Warriors are for killing, not for tanking! (ok I have no sensible reason to hate warrior tanks.. so don't ask rofl)