SRK had an interesting discussion on this matter after Evo had announced the 3rd Strike 2v2. Many players wanted to know why they weren't doing 3v3 like Japan, and the staff's answer boiled down to "the scene isn't large enough, 3v3 often means you have 2 good players stuck with a random scrub, and smaller teams = less potential for drama".
SF4 is the only game with a deep enough US scene to support 3v3, I think, but every other notable tournament game can do a good 2v2 at majors.
Also, as for the specific rules of a 2v2, I prefer Waseda style myself. This is where if you have team A+B vs. team C+D, A plays C then B plays D. If they split those two matches, the two winning players will face each other for the tie-breaker.
The straight elimination style (winner stays) is faster, though, and worth keeping in mind. This is what Evo used for the 3s 2v2, since they were obviously under a lot of time pressure.
Team matches should generally be one "set" (that is, 2/3 games in one of the two ways described above). 2/3 sets for winners, losers, & grand finals is fine if you have the time; Evo stuck with one set the whole way, but they had a ton of stuff to get through on Sunday.
