They were below average last year. I agree that they should be better this fall, but improving from below average to just average won't make a lot of difference.
Given last years scoring numbers, the scoring defense improvement of 5 pts/game to get Nebraska to average, would result in +3 wins. That’s considering how poorly yards were turned into points a year ago. I’d expect scoring and production improve in Year 2.
Such a defensive improvement combined with a scoring improvement of 4 points per game results in +4 wins or the 8-4 record many are predicting.
To get to those 10 win totals, Nebraska has to either pull a Northwestern and win every close game, pull an Oklahoma and win every shoot-out, or the defense has to be quite a bit better than middle of the road.