If your simply looking at skills he is one of the best the U21 could get on the team right now for his age group. The only problem is that probably wont be the case next season and in the following season due to his low potential (Allstar) so he will start to slow down on training, which is why not many allstars make it on the team. Many of his rivals will pass him up next season and the follow season. The only way he would make it on the U21 team is to make him an SF i think. If you were going to do this you would have to do this:
Rebounding up to respectable/strong
Inside Shot up to proficient/prominent
Then you could work on more guard skills, but if he is an SF he also won't cap out as quickly (According to what ive heard).
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs