Tennessee will be very cyclical going forward. Historically, they are a definitive #2 behind Alabama in the SEC. And while they've been down for awhile now, the right HC will get them back up - they can recruit regionally and get the talent necessary. But once that HC is gone, they'll fall back down to earth - and I say this because I'm not sure it's a destination job anymore.
I don't really see any reason for Nebraska to cycle back up. I can't help but blame their move to the B10. They went from being a big fish in a small pond to becoming a medium fish in an ocean, and there are a couple of sharks in there now. When I'm toiling around with football stuff and thinking of the B10, Nebraska is an, "oh yeah, and Nebraska" position now. A lot of that is a hesitation in remembering that they moved and a lot is their recent results. I just don't see any inherent reasons it's LIKELY that UNL climbs back up the ladder.