IMO very few fans have a good understanding of development in the NBA. Rookies that get drafted to good teams often have 2 good players ahead of them in the rotation which makes it really hard to break the first year or even the first 2 or 3. Players need consistent minutes and opportunity to play through mistakes in order to develop.
No doubt in my mind, if Haywood was still on the team last year, we'd have a completely different Donovan Mitchell and there would be a small group of motards who would consider him a bust.
Nobody knows for sure what kind of player Grayson Allen will be at this point, but nobody should be judging him from the spot minutes he's played so far, and certainly not based on one game.
Same goes for Tony Bradley. He's playing behind Gobert/Favors/Udoh who are all good and deserve minutes. Just because he hasn't broken through that rotation doesn't prove anything at this point. It's probably going to take some injuries and Udoh moving on before we get to see Bradley make or break.