Backcourt won't be an issue for Duke at all. Up front, on the other hand... all I'll say is Jahlil Okafor won't be walking through the door for them. Sean Obi is a big body and I'm sure his rebounding should translate fine. Who really knows about his offense, though? I sure don't. Marshall Plumlee and Amile Jefferson are fine role players/glue guys, but it's ridiculous to expect any more from them than that.
Then Chase Jeter has some skills and in time could be a really good college player, and granted, his skill set is MUCH different, but I don't see him bringing that big immediate impact Okafor brought.