As a fan, Dedrick Young was one of the most puzzling players I've seen in recent history. He was a starter basically from the time he set foot and campus, and while he was never flashy, he held that spot throughout his career. It should also be noted that two entirely different coaches staffs named him a starter so I think it's safe to say that he truly earned his spot. No doubt, he had some physical talents, but I always got the sense that it was more about his work ethic and ability to grasp his assignments.
That said, I can understand why many fans are underwhelmed by his career achievements. If I'm not mistaken, he never made All-Conference honors (or even an honorable mention). He racked up his tackle numbers in part due to the lack of talent around him. It allowed him to get on the field sooner and remain in that position unchallenged.
I'm happy that he tested well and that a 4-year starter at Nebraska still means something to NFL scouts. Maybe he can be another NU linebacker than underwhelmed in college (according to fan expectations), but went on to have a solid pro career (see Barrett Ruud or Stewart Bradley).