What Nebraska needs (and what it most certainly did not get in Riley), is the next Urban Meyer. People forget that when Florida hired him, he was just a fairly new HC at Utah. But he was up and coming. They took a bit of a gamble that he could continue to succeed when he moved to the big time at Florida but it paid off. We need to find the next Urban Meyer for Nebraska. Someone like Bryan Harsin (Boise State's HC). Someone who is relatively young and has a track record of success (and by that I mean a strong winning percentage) in the lower ranks of college football. Not someone who is barely above .500 after coaching for years.
The best predictor of future performance is past performance. It's not always right, but it is far more right than anything else. In a perfect world, Nebraska would hire a Sabin or a Meyer or a Les Miles, but that isn't going to happen. Sabin not leaving Alabama, Meyer isn't leaving tOSU, etc. Yeah, maybe we could pick up Richt but I seriously doubt it. Even if he would come, the $$$ is probably not going to be there. Richt is getting $4M a year now. Heck, Sabin is getting almost $8M/year!
So Nebraska has to find someone up and coming and give them a shot... not cling to the hope that a big name will come free and want to go coach in the cold plains of the Midwest for the same money he is getting in Tuscaloosa or Baton Rouge, where he's driving distance to his house at the beach and his golf course where he can play 365 days a year.