Davion and Agbaji have yet to be "professional bench types" yet in their careers, the coach didn't use Boosh, and Kelly is getting older.
Our bench was atrocious last year and those guys were all a part of that atrocious bench, other than Davion, who was also unplayably bad last year.
BUT, yes, Agbaji is young enough that a leap into effectiveness isn't impossible. He needs to keep hitting that corner 3, and his brain needs to keep catching up to his physique on the defensive end. Davion probably isn't young enough to take that leap, but he does at least have a very specific skillset that a good coach might be able to use to effectiveness....IF the rest of the team is pretty healthy and Davion isn't needed to do more than he can. But again, both these guys were legit terrible last year and have never been legit rotation caliber before.
There is literally not one "safely reliable" rotation guy on the roster beyond the starting 4 guys. Olynyk should be at least 1, though age and injuries are a worry there, and he's the most needed one because you don't want Poeltl being forced into full starting minutes either (unlike BBQ).
But the actual kids are intersestig - as bad as Dick was as a 20yr old rookie it wouldn't be shocking at all if he was actually decent at age 21. And then rooks are wildcards - it wouldn't be shocking if Shead/Mogbo/Walter/Battle could be effective. I'd be less surprsied by these rooks being good than the "young-ish" journeymen above.