And you also have to take into account the nature of the AAU team a guy is playing on. How structured of an offense is it, how common is it for guys to take quick 3's, to what extent is the player in question the lead dog on his team,expected to take a lot of shots?
I don't know the answer to those question with Markelle Fultz. I do know that Devin Booker shot some relatively poor %'s during the Nike EYBL 2 years ago, and that there have been other cases where guys who missed a lot of shots in AAU ball turned out to be really good shooters. Right now, from what I can see, Fultz has good form (always a positive, though not a necessity), though it looks more like a manufactured thing than the naturalness you get with the best shooters (like Booker). He's definitely an off the dribble player, though, not a guy hunting jumpers.