You know a wonderful way to quickly test pretty big changes? PTR. You know where we wont see any pretty big changes coming for a while? PTR. Really wish they would play around with the PTR a lot more than they do; it was really cool having the moira with the God fade, and I think more big ideas like that would definitely help the state of the game
I am a dev (though not on overwatch)
As a mechanism for testing changes you aren’t wrong. PTR is a great place to make low risk changes to the game. I think the piece you’re underestimating is how to decide what changes need to be made. With changes that have large consequences like 2/2/2, you need to collect data on what’s happening for a period of time to know what’s really working and what isn’t. Changes based on anecdotal evidence doesn’t work and leads to making things worse. PTR isn’t a good place to sample consequences. Scrims aren’t even a great place for that. OWL determines meta less than Poko believes (GOATS wasn’t invented in OWL, remember). It doesn’t reflect the OW community overall and if you overly rely on data there you’ll get nasty surprises later. PTR is usually meant for validating already well tested assumptions.