Quick play is only a matter of who will pick Hanzo and Widow first. Then the other players see a total disregard for any kind of team-play and they join the fray by picking up attack heroes too. I do try to play a healer or a tank and ask others to help, but most often than not to no avail. This is my view of quick play after playing 100s of games. Although there is a clear indication on the bottom right that tells people what to pick for a cooperative game to be most effective, people seem to disregard it.
The player’s perception of the pick is not at fault here. They have seen first hand the complacency with people who play snipers, so they can more or less predict what happens if someone starts off by picking up one. Constant experimentation leads to a more or less stable result pool. It is from this pool that people make their decisions from. Sorry If I went too deep here, but this is how it works in a few words.
I would like a mode where people join in as tanks/healers/dps and makeup a team with a makeup that makes sense. I do not have time to join a guild, nor to look around for people to do so. Not sure whether you agree with me, but quick play is pretty much unplayable and ends up being another shooter with very little cooperation between players.