Today I played as the solo player in a 4 stack. Terrible experience.
I cannot believe that they did not forsee how terrible it is to be a solo player on a 4 stack. You get flamed the whole game and blamed for any mistakes while if you are carrying, you get ignored. You can't make any calls and you are forced to play around them no matter how bad they are. It also becomes painfully obvious when one of the 4 is a low elo getting carried.
IMO, I think that dynamic queue should be limited to solo/duo/trio. 4 is a terrible experience for both solo players and 5's should just go play ranked team. Anything else is blatantly unfair, unfun and destroys the integrity of the ranked system.