this is what killed gw1 in the end. it would literally take 10 tries before a match would even start because it wouldn't start without full teams. I can't tell you how many times i start a match in ESO where teams only have 2 or 3 players... Anet learned a lesson and in gw2, they made sure heal class was no longer a thing for the meta making every class a hyrid capable of healing. And they started to heavily penalize quitting which helps to stop sync droppers from undermining the mmr. And they eventually limited premades to only 2 man groups.