Just the change he made to the coaching of the defensive line took them from horrific to at least serviceable/above average. Cam Jordan was a ghost before the change was made.
I'm not a fan of keeping Rizzi, but wouldn't be too upset if he's given a chance to build his own team and work with a healthier roster. Only if we have trouble landing some of the better candidates with our cap situation.
He did make some gametime clock management mistakes and maybe a bit too "enthusiastic" ;) at times.