One of the biggest reasons you need a strong walk-on program, as far as I am concerned anyway, is because of the nature of high school football in the immediate recruiting area. You have tons of small schools in Nebraska and Iowa with a lot of players who, because of the nature of the beast, are playing out of position. For example...when I went to high school we had a grand total of 30 guys on the squad. If you weighed more than 180 pounds, you were a lineman...no matter what. Had a friend who ran 100 yard hurdles and dash at the State track meet. Placed in the top 3 his Junior year in high school in each. On the football field, he loved to crack heads and run over people...but he never got much of a chance to do it come game time because, at 6' 4", 210 lbs, he was a lineman no matter how fast he was. That meant pretty much "zero" as far as any media coverage or hype was concerned...no college recruiters knocking at his door since he was an undersized lineman playing for a dinky school with a good record. Ended up going to NWMSU (who actually sent letters out to everyone on the team, inviting them to walk on with their squad) and went on to be a pretty respectable DIII linebacker. If he had walked on at Nebraska, I can't believe they couldn't have developed him into a pretty respectable DI linebacker or even full back...he had the size and speed, just needed some decent coaching on technique.
Tons of players still out there like that, potential stars at one position playing out of position as circumstances dictate. Any one of those guys is a potential starter somewhere...better with NU that with NWMSU or SDS or somebody like that.