Shamans rock in 5v5, and suck in 2v2.

This isn't a multiboxing problem, it's just general utility of the shaman class. A heroism is alot bigger when it's hitting 5 people than 2. Totems buff 5 people. No CC. No anti-CC.

It's not impossible, just rougher than most classes.

But WoW, apparently, wasn't balanced with dueling/2v2/3v3 in mind.