While I am glad others can see that O'Keefe carried the water during most of his tenure at Iowa, it is important to remember that Iowa's defensive scheme requires a pretty high skill set at all three levels and we were missing LBs in 2010. By the end of 2008 and during most of 2009, the defense was playing well because we had Clayborn and co. blowing up the line, Edds and Angerer finally "got" the defense and were beasts in coverage (which is very critical) and the secondary (Phil Parker's unit) was really, really good. In 2010, we were decimated at linebacker so we were doing things like dropping Clayborn back into coverage, the d-line had to play more contain rather than going straight after the QB (which provided more time in the pocket for the QB), and the intermediate passing defense on the TEs/slot receivers was absolutely atrocious because of a combination of time and inexperience by our LBs. We also lost Spievey from the secondary and he was a damn good corner.
The Iowa defense looks simplistic and the 2010 drop off is sometimes blamed on coaching, but to be honest, if you blame the coaching for the 2010 drop off, you either weren't watching the games or you simply do not understand football.