I will contend that under CNS, the defensive coordinator is (and always has been) far less important than the offensive coordinator.
I still view CNS as the de-facto DC. It’s his scheme, his coverages, etc..
The only significant modifications during his tenure at UA have been the personnel we recruit (smaller / faster at some spots) and more time spent in nickel and dime sets as some variation of the spread has become the default offense for most teams.
Personally I think a lot of the criticism on Pete was misplaced; modern offenses have gotten so good and rule changes and officiating have tilted so heavily towards offense that it’s nearly impossible to stop a high powered offense these days without said offense short-circuiting itself.
Things might be better with Steele (or any other coordinator), but if so, it’ll mostly be due to better personnel being in the right spots. At the end of the day, the system will be the same. I think CNS knows that, which is why I think Pete would still be our DC if Ole Miss hadn’t thrown a bunch of money at him.