We had a 'duel' map at one point (Duel at Dawn) (1v1), but it felt like it was drifting away from the core concepts of teamwork, so it was changed to a 2v2. I don't think they're likely to go that route again, but you never know.
As for the team stacking, we don't want to punish friends flying together, but we also want to protect random players from being stomped into pudding. Sure it can encourage some people to try harder, but others just get demoralized or upset. The new features should allow players to try and maintain fair matches if they so desire, without ruining the experience with their friends.
