You need to realize the Rein based comps won't comp unless there are changes.
And eventually that will happen. Rein comps will come back and zarya will be good, you don't need to buff a hero every time they fall out of favor.

I have to disagree with your opinion on triple dps being easier to execute than winston dva dive, I can see how you would think that it's just tdm but when you are playing vs coordinated teams it's much more than that. It's not really worth debating this point since it doesn't matter much big picture.

Generally speaking in winston dva dives you decide where you want to fight, keep an eye on enemy cds, then decide to either dive on a target or wait and counter dive. Sometimes your zen just dies, but you know going into the fight what kind of trade you are willing to make and play accordingly.

Also, reaper is a good counter dive hero but he's not when dva is as good as she is. My suggestion makes a rein reaper comp a possibility as counter dive (maybe? dunno would have to see it tried.) but as long as dva can block all of his damage for free hes not gunna be as good at his job.