On the pass rush, NU needs someone who "can get there", preferably in a hurry. One or ideally two of those guys would help enormously, as that opens up things for the guys who can "get there", but need a little help. Think of the sacks Crick got because the opposing line had to account for Suh.
As for the players who are up for a good amount of time on the field, I remember the shock of horror when Barry Turner went down in 2008. Pierre Allen stepped in as a RS Sophomore and performed well with 52 tackles, fourth on the team. So we don't know yet who (if anyone) might step up and perform above expectations. Stille has played meaningful snaps since his RS freshman year. Deontre played as a true freshman. Damion needs a couch to 5K program, but if he can improve his fitness he can be a valuable space eater in the middle. Add Green, Ty, Rogers and Wildeman, plus Riley (NC > JUCO > NU) who was brought to add immediate depth at DE.
I would think the big issue will be determining who plays at NT. Damion of course. Green and Ty are the obvious other candidates, IMO, but those guys can also play at end.