I've been doing 2v2 with a couple of my exisitng 70's (feral druid, resto shammy) and our rating sucks on toast. When I first started I seemd to find a lot of teams that were either dumping points or just really really bad (Pallys and moonkin that didn't heal, at all. Thinks like that). Since the most recent point system changes though, all I seem to find are overgeared teams that destroy me in seconds.

But more to your point, I'll echo what others have said. 5v5 you can do pretty well because of the tremendous focused burst damage you can do. 2v2 seems to be more about Crowd controll, interrupts and especially movement. Which of course is a multi-boxer's big weakness.