While at Nebraska, JBD lacked that "killer instinct" you want D-I athletes to have. I remember reading an article where JBD was asked, "If you could have any super power, what would it be?" His answer was "invisibility". I'm not sure a guy who wishes he was invisible is capable of being a better college player than Maric, but he absolutely would have been a welcome addition to any roster in recent memory.
It appears JBD has found some confidence, improved his game, found a perfect fit, or whatever now; but as a 20 year-old kid, I don't think him being healthy would have necessarily equated to a drastically better performance on the court.