matchmaking is definitely unbalanced but I believe they didn't anticipate so many players queuing on trash builds. I have to leave matches all the time because 2-3 players will be afk while the others are severally undergeared and get one shot from 100%-0. Even if I could hard-carry baddies through a match I wouldnt want to because i'd prob get paired with them in a higher elo.
Skill level and class knowledge is important but build is prob 80% of 6v6...there needs to be better matchmaking based on this.