I guess my hidden rating has gotten high enough that last night my friend and I were fighting a lot of the same high level people. I know your level only indicates time played, but you can probably assume that when you're seeing multiple level 55-60 people in a match that you're playing against the real overwatch diehards. I've done nothing but play this game since it came out and even took a day off work, and I'm 'only' 34.
Anyways, I rarely have issues with character selections now. People pick what is needed, I play support every few matches and it's fine. I don't have AS many problems with them fighting over stairs in a corner but there's still a lack of grouping up together on offense.
My main problem is the complete and total absence of situational awareness. When do people start backing up when they hear FIRE IN THE HOLE, looking up when justice rains from above, or taking cover from high noon? So many times I'm the sole survivor of an ultimate.
Also most Reapers now have figured out that people don't look up so I'm sitting here watching one basically do the equivalent of this while up on a ledge:
And of course you can guess what would happen to my clustered-up teammates who don't look at anything but what is in front of their crosshairs. My favorite was the Hanzo on Numbani defense where all of us immediately fell back to defend, but this guy didn't notice and was just standing behind a bus aiming at the enemy spawn. They all just ran past him and he was still just aiming at that one spot when they turned around and blew him up.
I have started seeing good play from people though. Tracers capitalizing on Zarya ults or Lucio reacting with his shield when we all get caught by one.