We saw those fruits the 1st half of the bowl game. Also G&D run a 4-3 under on 3rd down, same 4-3 under Butch and Jimmy ran( although I have no clue whats going on in the secondary). I am disappointed too about the performance the last 3 years but I see hope with the 1st half performance in the bowl game and the incoming recruiting class.
Jimmy and Butch based their defenses on quarters coverage. It was something between classic cover 4 and cover 2. Many schools use "other" terms to describe this coverage like cover blue, read 2, palms, etc.
The coverage they used was based on pattern reads. Any pattern read based coverage really ends up being man coverage after the routes have been dealt. We have never been known to be a man coverage (with help) team like some people like to believe. We run the same stuff today (along with other stuff). Everyone runs it.
The coverage can be tweaked in many ways, it can be soft or hard -- whatever. We like to play a soft quarters when we do actually use it. Remember T. Howard's pick during the UF game? That was a textbook quarters read. He skated with the #1 receiver, while keeping his eyes on #2, broke on the pattern and made a play on the ball.
People don't understand that you can't base out of a 2 man coverage. You're going to get murdered in the run game, especially when the quarterback is a threat. It's mostly used on pass downs. 43 man coverage teams usually base out of an under front, coupled with cover 1 or "man free" in the back. (outside leverage man with help in the middle). Teams like USC and UF (charlie strong) made this famous.
A lot of people lose sleep on scheme "problems," and I just think it's silly. Pretty much everyone runs the same stuff. The biggest problem is execution ,TALENT and DEPTH. That falls on the players, coach, and recruiting -- everybody. It's unfair to scapegoat one dude. He can't possibly be that bad of a coach. There have to be other problem areas.