I think your thinking about developmental in the wrong sense. NXT isnt wrestling school. It's developmental. Those belts are meaningless and some dudes are meant to be jobbers it's fine wrestlings fake bro. Those dudes dont care about winning fake matches. It's all a show.
People exclude the ROH dudes, like Seth or Sami and say "ahhhhhhh they were in the indies, so they dont count."
Nah... they dont go to NXT to learn to wrestle. They go to "develop".
"Develop" a character that's marketable and works for television.
"Develop" an entrance, and understanding of working the hard camera/audience etc.
"Develop" a moveset and signature style that fits what the WWE wants.
"Develop" a look, mannerisms and a voice/mic skills in promo class.
All those things count as developing. I remember watching Nia Jax on Breaking Ground and she's with a seamstress picking out colors and fabric's, a logo etc. That's developmental too. Sami Zayn developed from El Generico and he continues to develop on the Main. He had some things that just worked but you can see his changes as well.
Even after you get called up, youre still developing. It may take a year or two to see what anybody can really accomplish. It's like "Stunning" Steve Austin, was Stone Cold in developmental. Or Goldust was "The Natural" Dustin Rhodes in developmental. It's the difference between "Brood" Edge and The "Rated R Superstar" Edge, it takes YEARS to develop. I saw him and Christian get absolutely squashed the other day on The Network. Thank god it was no IWC then. If we judged people like this back in the day, The Rock wouldnt be The Rock. The Hardy's were jobbers for YEAAARRRRSSSS... They wouldnt be the Hardy's etc.
Someone like Tyler Breeze who is a good hand and works hard, can get repackaged and come back with a gimmick that really suits him. Someone like Seth is the perfect example of someone who was able to have his character develop organically over a few years and now he's at the top of the card.
NXT is just a starting track.
Baron Corbin, has all the qualities and attitude of Main Event heel. Let him continue his development on RAW, it's not too soon at all. He's gonna be around for years. This is just the first version of him we're seeing.
Dana Brooke has the look, pedigree and swag of a star, she'll develop more on TV.
My point is, it's really too hard to tell whose gonna do what at this point. These dudes, even Roman are really just starting out.
I don't think a call up, is them saying "oh put this guy on Good Morning America". It's just saying on "okay we're going to throw you in the fire, to learn the road, learn the politics of the back, learn the grind and start your journey on a bigger stage."
Dudes like Bray are gonna be around for years. Vince feels that he's the next Undertaker and he's gonna win the strap eventually. He's only like 28 years old. If you think in the next 10 years this dude isnt main eventing Mania your crazy. Writings on the wall. Just cuz he loses all the time so what "credibility" is some shyt the IWC made up. The Brood got there ass whipped all the time. Nobody even remembers half that shyt when they want to make you.