@ippig agreed. If they had a larger playerbase I'd suggest the thing that World of Tanks did where they at least tried to split platoons (essentially groups of friends) among the 2 sides as evenly as possible. This still backfired at times as a platoon of a top clan would be against a team of noobs but at least they tried to do this.
We did get split sometimes in GW1 and 2 when a couple of us played together, but it was pretty rare. I'm not a huge fan of forcing people to split their groups but if it helps the game in the long run then it needs to be done.
Edit: I read my post and it may not be 100% clear. WoT would take the players currently looking for game (and based on vehicle tiers) and try to put an equal number of platooned players on both sides. For example if a bunch were playing tier5 and they had 2 platoons of 3 and 3 of 2, they would likely put the 2 big teams on one side and the 3 smaller ones on the other side. It didn't guarantee balance of course as player skills could vary wildly here, but it was an attempt to avoid pub stomps, but they certainly still happened.