It seems to me like Riley probably didn't realize the difference in scrutiny from OSU to NU. Banker's stuff worked here and there but not nearly as many cared as much when it didn't. He did have a couple good years. They were also #76, #101, #84 and #86 during that time so there was definitely more bad than good. Plus there wasn't an entirely large amount of defense played in the Pac-10/12 overall so it wasn't so much outside the norm.
I'm sure Riley realized it to some extent here but I really think having Devaney around made a huge difference in deciding to change.
I think when we look back on this time period in NU football history we will really realize what a serious impact Devaney had on this program. Guy has been Riley's confidant essentially since he was here. I don't know that Riley makes some of the moves he's made without Devaney here, whether you're talking hirings, firings, or schematic changes.
Having BD here as essentially acting GM has been a major success and I hope he enjoys it enough to stay here for a long long time.