The first possibility is that Chizik hasn't figured out to involve himself in the defense while still handling all of the tasks of being a head coach. After all, Nick Saban's Michigan State defenses weren't overly impressive, nor were his initial defenses at LSU. Mark Richt would also seem to fall into this category, as he won at Georgia in his first five years despite underwhelming offenses. Richt was either spending all of his time on other head coaching functions or he was overrated as an offensive coordinator when he was at Florida State.
A second possibility is that defense is more about talent than coaching (it's easier to scheme around talent issues on offense because the offense has the initiative) and Auburn is suffering for Tommy Tuberville's diminished recruiting in his last several years on the Plains. Again, the Saban example is instructive. Nick's defenses weren't great until he had time to recruit at LSU, at which point his career took off. (He won a national title in year four.)
The third possibility is that Chizik was overrated as a defensive coordinator. Yes, he won a national title with Texas in 2005 and produced a very good defense, but is it really that hard to produce a good defense with Texas's talent relative to that of its opponents? His 2006 defense was pretty good, but nothing special. (The Horns finished ninth in the Big XII in pass efficiency defense that year. I'll admit that I don't remember Texas's defensive talent in 2006 and that would be a major consideration. Even in Austin, it's possible to have to make chicken salad from chicken s***, relatively speaking.) Chizik's defenses were very good at Auburn, but he was coaching under a defensive ace in Tommy Tuberville. WBE makes this very point:
Tubby was widely regarded as a Miles-type CEO (and Elkon seems to echo this viewpoint) whose success rested on whoever he happened to have hired as his offensive coordinator, but I think this does a disservice to Tubby’s incredible defensive record. When you consider that it didn’t matter who the DC was–Chizik,
Muschamp, Rhoads, whoever wasn’t David Gibbs–the defense was going to know its business. You ask me, Tubby was quietly more Saban or Meyer than Miles in his affect on his team’s on-field performance.
I am often leery of coordinators who are successful on the side of the ball on which the head coach has obvious expertise. (For this reason, I was not as enamored by Kirby Smart as many Georgia fans were. Dan Mullen will be an interesting test case for this.) If this is the case, then Chizik falls into the George O'Leary category: a coach who isn't especially good at his specialty, but who succeeds anyway because he has a great coordinator in his weak suit. Chizik will therefore be defined by how long he can keep Gus Malzahn and then whether there is a good replacement when Malzahn gets a head coaching job. The luck/timing element comes into play again.
WBE's discussion of Tuberville is interesting because he is going through the same re-evaluation of Tuberville that I am. Several summers ago, I started (but didn't finish) a series of posts comparing SEC coaches to World War Two generals. Tuberville was going to be Eisenhower: a successful general whose skill lay more in managing the egos of his subordinates than in directing divisions here and there. After the Tony Franklin debacle, a different picture emerged. Tuberville and his position coach buddies had asserted themselves to the point that Franklin wasn't able to do what he wanted. In retrospect, Tuberville's consistently good defenses indicate that he had an active role in that area. If I had to do the series now, Tuberville would be Hitler (minus the whole genocide thing): had success early, gained the reputation of a gambler, ultimately undone by meddling too much.
And for the hell of it, here is the rest of the SEC (minus the coaches who have not yet coached a game at their schools):
Spurrier/Guderian: an innovator, but exposed when faced with opponents with more of everything.
Saban/Zhukov: ruthless, brutal to subordinates, headstrong, very successful, saved an empire on the verge of collapse.
Meyer/Patton: great offensive mind, sharp at understated parts of the job, successful in multiple theaters, problems with the media.
Nutt/Wingate: crazy man on the periphery
Petrino/Rommel: top offensive mind, doesn't always pay attention to defensive issues, questionable loyalty.
Richt/Bradley: unassuming, competent, likable, loyal to subordinates, upstaged by Patton.
Miles/Montgomery: early success, followed by strange vacillation between conservatism and aggression. Market Garden and the last drive of the Ole Miss game seem to fit together in the realm of disasters.
Mullen/Ridgway: looks promising for the next war.
I'm drawing a total blank on Chizik.