Why did Spagnuolo stink as Saints' DC? (merged)

I just think CSP did not mix well with him, and Spags' defense scheme did not fit. I am not taking anything away from Spags' past or current accomplishments. His defense in the AFC Championship against the Raves was really phenomenal. It just did not work here with CSP.
CSP couldn’t mix well with a lot of people. Couldn’t tolerate another strong cia h in the building it seems.

A bit dysfunctional and probably part of why that side of the ball stayed dysfunctional so long while he meddled in it.