The FUGA game may just be our saving grace.  Anyone think a 5'10" college player who can't guard for shit, will be able to check 6'5" elite athletes on a nightly basis in the NBA?  Cooper is a supreme talent on offense, but he's a liability on D even at this level. 
if were being honest....I like the guy and he's dynamic....he has great vision and can dish it out as good as I've seen, but he's a subpar shooter at the moment. He has no jump shot, he has no 3 point shot, no mid range shot, no fade away - he gets a lot off floaters and layups. And at the stripe drawing tons of contact. He is still a project at this level. But NBA teams don't usually choose guys in the 1st round that need to develop a jump shot. Just sayin....And that's just the offensive lackings. 
As you mentioned above, there is the D SIDE which is his real liability. 
The guy is def a spark for the team, and he changes the way other teams have to run plays but his game has a ton of gaps.