Besides the other benefits which may be compensated for with other classes, the one thing I couldn't get past when deciding who to multibox with was the fact that a shaman team will pretty much never have to corpse run individually, and rarely have to at all. As long as any one of them is alive, you can res, and most of the time you could have a self-res up as long as you're not in a bad position to do so. Even if they all died, running them ALL back at once is no problem. I don't think any other class even comes close to the ease of shaman death recovery.