I just looked at defensive rankings for 6 stats for OSU and Nebraska 2002-2015. I'd like to put it into a spreadsheet, but I will have to wait until after work. Here are some observations:
Overall, the first 6 years of Banker at OSU were good/great with the exception of one year (2005)
The last 6 were average/bad with the exception of one year (2012)
Run Defense was pretty consistently good in the first 7 years, with top-25 finishes 5-of-7, and two top-5 finishes.
Pass Defense was pretty consistently average/bad throughout his tenure, with a #22 best ranking in 2009
INT and sack rankings were up-and-down, but a lot of top-ten finishes in there. I'm guessing that it was more of an individual talent thing?
Also, as bad as Banker's last 5 or 6 years were at OSU, ALL of the 6 defensive rankings for the Beavers in 2015-16 were lower than Banker's lowest year. Horrifically bad Defense.
Nebraska's #9 Run Defense last year matches Bo's 2009 rank, and beats Bo's 5-year average since then (70th).
Nebraska's #121 Pass Defense last year is the lowest in many, many years, beating 2004 (110) 2007 (84) and 2008 (89).
Bo's 4-year-span of Pass D dominance (2009-2012) compares closely to Banker's 5-year-span of Run D dominance (2003-2007).
Both Coaches' INT rankings are similar. Including 2003 for Bo, he was top-11 3-of-8 years. Banker was top-10 5-of-12 years.
Bo was top-15 in sacks twice, in 08-09. Banker was top-5 in sacks in 06, 07, 08.
Bo's increase in defensive rankings in 03, and 08-09 are striking. Amazing, really. Banker in 03 maintained a similar or slightly better ranking compared to 02.