SC2 for example does not have this problem on the competitive ladder, is this a different system?
its because SC2 both players connect to a server, in coh2 both players connect to eachother (or a peer to peer system).
the only server that is used in coh2 is for the match making then you connect to the player; its why if one player is lagging both lag. (well and obviously for your stats.)
well you can always leave the game if teams are stacked no one forces you to stay + you can just bring some of your friends with you and even the teams anyway.
a lot of what i saw was players making a game stacking 1 team then having another one of there friends join the other team and right when the game starts drop the other player. causing an uneven match i didn't stick around on that and went to auto match, that and i preferred vp games with standard resources which lobby never had. i think a way to minimize this is to make lobby games unranked. but showing the auto-match rank to get a estimation of skill.