with all the issues with unbalanced teams (especially in 3vs3) I think the easiest way to make people happy would be to have a "Join up" option at the end of the game - once you play with a teammate and find out that they are okay (no matter the level they are at) and they supported you in that last game it makes sense to play with them again
even if you play a couple of games till you find one partner to join up with it will make the experience better and you will have a better chance of winning when you know someone's style on how they play
even if you play a couple of games till you find one partner to join up with it will make the experience better and you will have a better chance of winning when you know someone's style on how they play