A few more PTR observations. This only from competitive, since it's the only place to get good group composition since QP is basically 2-4 Ana minimum so getting a decent view of things is impossible.
I played a lot of Ana, Zenyetta and McCree, almost no D'va.
Nothing much has change on my observation on Ana. I'd just point out since I think I didn't before and not sure if it was mentioned here. But in scope mode her shot are hitscan, and when in regular mode, they are projectiles. I'm very confident that if her grenades and ultimate are not nerfed that she might end up being in used in most groups. Her heals are decent, her damage is ok, but her utility is huge.
Zenyetta is just a beast, his discord orb and damage was always very good, but his survivability was awful...now that is survivability is fixed, might be too good...he's simply awesome, his damage output is better due to the fact that he survives better, and doesn't die, or need to hide as much. Since it's almost all shields that regens, it's really good. Hide for a few seconds and you're ready to go again. The fast movement of his ultimate is a great improvement, since normally you were not usually with the group, as you player more range, and would get to the group late when using the ultimate reactively...that's no longer the case, you can pop your ultimate and run to the group...or run around a rather big area to provide healing to members spread around the control point...it's a really big change
McCree is in my opinion too deadly, even with the Mercy nerf back to 30% he does way too much damage from range.
Right now on the PTR, the new meta is often 3 supports...Ana, Zenyetta and either Mercy or Lucio...or Symetra on the maps where she is really good. Zenyetta essentially provides DPS that rivals the offensive classes while still providing solid healing. While Ana doesn't provide as much damage, she will get her fair share of kills, and offer a decent healing, and GREAT utility. And we're not talking gimmick group here...but seriously competitive group...the amount of healing and utility that a Ana/Zenyetta/Mercy can bring is ridiculous...and it does so by not reducing team DPS but that much.
That 3 support team will see almost all the tanks be viable. Reinhardt being the favourite because he probably makes the best use of Ana's ultimate right now. D'va is almost always used also, is either as a replacement for Reinhardt or as a second tank. Winston, Roadhog, and Zarya still see some play. Defensively, only Junkrat and Mei sees play right now...Widowmaker, Hanzo, Bastion, Torbjon are all but dead. On offence McCree is the only that still sees regular play, Reaper and Genji a little...but Tracer, Pharaah and Soldier 76 are all but completely gone.
Now I realize that this is the PTR and people are playing with the heroes that have changed a bit more, and the new hero...but I think a lot of this will carry over to live unless there are more changes before this hits live. Oh, of course part of this has to do with the fact that you can't hero stack in competitive...which just by itself changes group composition a lot.
It feels like a new game almost. The no hero stacking, a new hero, 3 classes receiving significant buffs. I hope it hits live soon. I haven't played a single live game since this hits the PTR as it's way way more fun.