Well, from what I have read a lot of folks are doubting whether Fowler, Ray or Gregory are ready to step in and play in the NFL from Day 1. Landon Collins is definitely at a need position, but a strong safety is not a #5 overall pick. There are no cornerbacks or tackles that look worthy of a pick at #5 either.
So, that leaves us with a decision if we can't trade down. We may have to take a younger player with the size and raw talent to be successful with good coaching like Shelton at an anchor position of real need on the defense.
Unless you have a NT like Casey Hampton (ex-Steelers) or Haloti Ngata (Ravens) your 3-4 alignment is going to fail to meet expectations.
If we have to work to develop a guy that could be a great asset, I would rather do it with a NT than another OLB like Orakpo.