5-man and 4-man premades should be put against another 5-man or 4-man premade 100% of the time.

It would basically clear up all the gripes about being put with a different number of premades. And the solo people with the 4-man will have one on both teams so it should be about even there.

Ofcourse this would increase there queue times but if you wanna group together its something you should trade-off.