I would imagine that Giles could play a position at Wake that is more suited to his skill set and more suited to what he will do/play in the NBA. It seems that bigs fall into one of two categories at Duke. If they can handle the ball and shoot from three, they play more of a small forward position. Guys like Singler, Battier, Winslow, etc. My understanding is that though Giles is athletic, can run the floor, has decent handles for his size, etc., he is not a perimeter oriented player, so he wouldn't really fill that roll. The other bigs that have done well at Duke have been more of the back to the basket, post-up, center types. Guys like S Williams, Boozer, Okafor,and whatever the name of the guy that was there 2 seasons ago (their one and dones are starting to run together - can't really distinguish them any more). If I recall, the knock on Okafor this draft (and part of the reason he dropped a little), was because he hadn't shown that he had an NBA type game - because he played more of an old school, back to the basket game. It also seems like the Duke bigs that have underwhelmed relative to their recruiting rankings are guys that couldn't really play that perimeter position, but weren't really a low block type of banger. Guys like Jefferson, L Thomas, McRoberts, S Randolph, etc.
Am I saying that Giles will miss out on the NBA by going to Duke? Of course not. However, I can almost guarantee you that Manning will make sure that he plays a position and type of game that will be most similar to what will be expected of him in the NBA.