He isn't a great athlete man. He has a good first-step, but that is about it as far as above average NBA athleticism is concerned.
Measurements don't mean jack if you don't do it in the game. Luke Babbit had a 40 inch vertical, which is probably top 5% in the NBA, don't try to tell me he is a top 5% NBA athlete.
You might be right, that's a thing that bothers me. He might actually be better athlete without the ball, which wouldn't fare well in the league... I guess we'll see soon enough... I want to see him get an NBA body. I think Alec Burks is a good comparison for what I want him to look like in a couple of years time. They had similar bodies at the time of the draft:
Alec Burks: Dante Exum
Age: 19 vs 18
Height w/ shoes: 6'6'' vs 6'6''
Weight: 193 lbs:196 lbs
Wingspan: 6'10'' vs 6'9.5''
Standing reach: 8'7.5'' vs 8'7''
Right now Alec is 211lbs and his body looks great on his 6'6'' frame. If Dante can fill up and mature the same way I hope this will help him more confident attacking the basket.