GT, nicely stated.
I remember that when he arrived, everyone was worried he was Ground Chuck 2. Well, he isn't. I think he has a few core principles - things he think smart teams do - but he doesn't come across to me as someone who is married to a specific scheme.
I don't think he really underestimated NFL QBs as much as he overestimated what the Buc corners could do.
The coach does have some longstanding core principles, especially defensively. I wasn't trying to portray Schiano as unyielding. Rather that the scheme changes I'd look forward to would be rather minor, not major, changes. As you said, he's learned something about his corners and likely will make a serious push for legitimate staring caliber talent in the offseason. I'd have to believe that would make as much difference than any type of scheme change.