I think it's a pretty bad expectation to think that all your QP matches will build into a solid team. I'm not sure why people would think this would be the case, people are going to play what they want at times when they want to. Of course it would be nice for there to be great synergies within your team but that's just not realistic at all times...
It is not realistic at all times, but i'd expect it to be most/many times. Yesterday for example I played 5 QP matches because a friend did not want to play comp. I won all 5 because NONE of the enemy teams had a tank. Over the course of 5 games i did not see a single tank, just widows, hanzo, lucio, torb, bastion, mcree,sombra,sym,etc.
It is just sad to crush anyone because (since we were 3 people) my team just pick the right roles. It is not like most of us are good players (i'm diamond, the rest are gold), yet we won like we were pros playing against old people.
If i queue alone the inverse happens. My problem is that people REFUSE to cooperate ,like at all. I'm playing rein and see a reaper flaking us on the left. I say reaper on the left. He manages to kill hanzo, widow , soldier and make an assist on tracer; like people listened to me and thought something like " meh, i don't care".
you can't expect that the game puts you into a team where players like playing those roles. I'd rather lose a game and play as a hero i enjoy than slog through a round of playing dudes that i have no interest in playing, while the guy who whines about the change is playing his favorite hero.
I always change to whatever role the team needs the most. The only chars i "can't" play are the snipers because i don't do headshots very often.
The problem is the bold; this is not a COD where you only have 1 char; you "should" play 2 or 3 chars from each role, if you can't you are just cuting both your fun (since you are forced to that char everytime) and diminishing your team capability (you can be hard countered).
Is QP not for praticing both using 1 char AND teamwork? For most people no, QP is to play OW like COD.