I'm just a believer in the 'play with friends' mentality, damn my extrovertedness!
Now, to counter your point, if your rank is tied to individual performance, I feel like that just opens up a big exploit, and a big "NO, ME ONLY!" mentality. I feel like it wouldn't encourage team play. Making it so that your rank (and thus who you play with) is tied to just how you do individually, you may find that people will be extremely selfish, looking out for themselves and trying to grab up all the points they can so that they can level up as quickly as possible, completely removing the "team" in teamplay.
Now, say "nah, that will never happen!" and I guarentee it will, even after you let the system sort itself out. it's basic player psychology. You tie the reward to individual play, you'll get people who play like individuals. You make the rewards tied to the team effort, you'll get more attempts at cooperative play. It's basic play psychology and basic game theory. You don't have someone trying to lead the team? You be that person.
The other option, which may or may not be better (which I've seen games use to varying success) is to have two separate queues. Solo Q and Team Q. If you're alone, you can use Solo or Team Q, if you're brave. If you're with people, you'll only use Team Q. That way, it ensures that only solo players are against other solo players, so while you might still get bad teams, the other side has an equally likely chance for a bad team too.
Do I agree with what I said before is a crutch for bad ranking design? No. I wasn't commenting on the design, I was directly commenting on how you (you being a general term, no you specifically YM) play. You're playing alone in a team competitive match where you can go up against teams of multiple people, of course you're going to have a bad time you cotten headed ninnymuggens!
tl;dr: To me, it's a team ranking system, for a team based game. Play it with a team (2 or more people), you poops.
