We played this Cho'Gall group last night. There were 4 of us in our group, and we hit them twice in a row in Unranked.
Dominated them the whole game, and I mean fucking dominated. 4 level lead in first game, 3 level lead in the second game. Just as we were getting level 20 in each game, however, people got too confident and we'd get a death. Then something would happen and stagger a second death. Then our 4th, who was abso-fuckin'-lutely awful and was just a random from another friend's friends list, would pile on a 3rd death and then a 4th as soon as he was back. By then, they were level 20 as well and we just couldn't burst them quicker than they could us.
We played 4 games last night and that 4th in our group died at least 7-9 times in each game but felt he wasn't overextending or doing anything wrong. I was gonna kick him after game two, but let him stay all four games...I won't make that mistake again.
To be honest, that's why I've played more Overwatch lately. If I have idiots on my team in Quick Play, I can just leave. If I'm in Competitive, I can at least switch to some hero I want to work on/learn (and can also just switch in QP). The games in QP are over in like 5-10 mins tops, and if I lose at the end of a game it's often a hard fought contest....not one that we dominated for 99% of the game and lost one fight and GG. It just feels better as something for me to be casually invested in. That's all IMO, of course, but it's kind of where I'm at. The fact that every given night we could feasibly put together a 10-12 person group in OW helps a lot too.