He was getting better but I don't know how far he would have gotten with Robinson. I don't know what on earth possessed him to hire him as his DC and keep him no less. While I like Rich Rod as a coach and think he can be successful in certain jobs, the defense is a caveat to me just like many other spread coaches.
Look at Dabo, he's not a spread coach but they've used the spread with Morris and now their new OC. However his DC Brent Venables has been steadily increasing their defensive numbers over his time there to the point where they're in the top 10 the last couple years on defense. That's like the ideal situation, I'm willing to settle for top 50-65. If Venables had a little better demeanor, supposedly known to be a hot head, I wouldn't have cooled on his as candidate otherwise I think he'd be good.