I "hope" that there is some sort of acclimation going on but I find that hard to believe if what we've been told is true. Weren't we all told and hasn't someone in particular argued that Morris is running the same exact defense as Staley did last year? If Morris is making adjustments, that would mean that Staley's D was the problem or it means that he wasn't actually running the same D.
Without getting hung up on terminology, something looks different and it isn't just the players who have been replaced. That it works against cellar dwellers is fine but I know that I am not comfortable at all with it working against the top teams. The only healthy, fully-functional offense we've faced was AZ and they ate our lunch. I don't think anyone is suggesting that our defense is bad all the time and won't work at all. But I think the real question here is will our defense stop playoff caliber offenses?
So far, I don't see the evidence to believe that is the case. Our DL doesn't dominate. Our secondary has exploitable weak links. Our defensive attitude is passive and reactionary. Waiting for other teams to make a mistake is going to kill us against teams that can sustain drives. Like it already has at times.