Not saying that Banker is the long term answer, but...
Comparing 15 to 16, our rush D got worse, but our passing, total, and scoring D improved. We allowed 50 less yards/game and 5 less points/game.
Were the offenses we faced this year that much worse than we faced last year?
2015:
#64 Total D 400.4
#92 Yards/Play 5.88
#9 Rush D 109.9
#32 Yards/Rush 3.77
#122 Pass D 290.5
#84 Yards/Att 7.5
#75 Scoring D 27.8
2016:
#22 Total D 350.6
#46 Yards/Play 5.40
#36 Rush D 141.0
#59 Yards/Rush 4.28
#42 Pass D 209.6
#25 Yards/Att 6.5
#30 Scoring D 22.8
And not that I fully understand advanced stats, but they also show improvement
DS&P+
2015 #57
2016 #21
DFEI
2015 #70
2016 #51