Because of how bad Nebraska has been since Frank left, there has been a lot of revisionist history about his coaching tenure. We were still pretty good the first couple of years under Frank, but after that the decline was palpable. We continued to beat the patsies on our schedule (and back then, we were fortunate to have a schedule mainly made up of patsies), but we began to lose to good teams consistently. The most obvious sign that something was seriously amiss was when we got pasted by Colorado and Miami after delusionally believing that we were a national championship contender. Clearly, we have had a lot of swings and misses in our coaching hires since Frank, but that doesn't mean that all would have been well had we kept him as our coach. He was not a long term answer. He may have had some success in the MAC, but he is not a good Power 5 coach.
Ryan Day seems completely different to me. Everything I see tells me that he is a great coach who has a bright future.