I believe Texas's scoring offensive numbers were better than their total defensive numbers. His scoring offense including #1 in 2005 were very good, and imo, scoring statistics are more telling than total yardage.
From my very unscientific observations of Texas fans' reports, stats, and other dubious stuff I've found on the internet.
Positives:
Good at developing QB's. He's had a lot of talent to work with at QB, but he's gotten a lot out of them as well. Colt McCoy, was not your typical 5 star Texas QB recruit, and he developed into being one of the best college QB's in the game. VY, is not a quality pro QB, but the guy is one of the best college players I've ever seen. In retrospect he deserved to win the Heisman in 2005.
Does a very good job at matching schemes to available talent. Texas was almost strictly a "pro-style" offense prior to VY, but Davis very effectively adapted the offense to a zone-read that matched VY's athletic strengths. Similarly with Colt McCoy the offensive schemes were tailored to fit his abilities very effectively.
He's very good at putting together game plans. Analyzing film and developing a game plan that takes advantage of the opponents weaknesses.
His team's managed to be among the most productive offenses in the country many times under his tutaledge.
Negatives:
Reputation as a poor recruiter. He's said to be lazy and unenthusiastic about recruiting.
Fails to make in-game adjustments. This is a frequent criticism of Davis fromTexas fans. His pre-game analysis was good, but his in-game adjustments were poor/seemingly non-existent.
Predicable play calling. This is a consistent criticism of him by UT fans. Especially in an over-use/dependency on the bubble-screen.
Horizontal and not vertical passing. The team had frequent wide receiver screens but rarely threw slants that could get wide receivers yards after the catch.
Those are some of the more frequent comments I've read.
From what I've read of the 2011 Texas season(the year following Davis's 'resignation') much of the improvement on offense can be attributed to better play by the OL. How much of that is attributable to a new OC is hard to tell, but I suspect at Iowa the bulk of the responsibility for the offensive line schemes/formations will be from the Ferentz's. One thing I'm sure of with KF and Brian is that the offensive line will be in position to make blocks and will have good technique when they are. It sounds like the Texas line, and offense generally was in a transition year on offense and that and the sense that the Texas offense had become "stale" was more responsible for Davis's ouster than anything.
The first thing that struck me in looking at what Davis did at Texas and what he'll go here was the obvious talent gap between the schools. Will Davis be able to raise the level of athletes to perform better at Iowa relative to their recruiting rankings than he was able to do at Texas. That's a hard call. I don't believe it's a given that he won't be able to get kids to outperform at Iowa because he's worked with mostly stud athletes at Texas. One his reputation as a good developer of QB's. The strength of Iowa's program is in player development, not schemes and i think in Davis KF sees a guy who can develop QB's. Teaching coaches are KF guys and I think in Davis he sees someone who fits that mold. Not sexy play calling but a developer or QB's. Second, one criticism of Texas's offense the last several years has been the OL. That's not likely to be the case at Iowa. Their weakness is our strength. So, while Davis is used to working with a lot more overall talent. He's not likely to have had an offensive line, and an offensive line coach/es like he'll have at Iowa. That's a strength he can play call around and count on.
I'm not in love with this hire, he seems too much like KOK. A consistent coach, a good "teacher" but a uninspiring and predictable play caller, and I wonder how well he's going to scheme around the fact that he'll simply have a lot less talent at the skill positions to work with, but I'm beginning to believe this is a hire that has a good chance of being alright and a slightly better chance of being better than just alright. KF's strengths are really in the run game/OL, and Davis is a better passing guy. So, his coaching talents may very well compliment KF's. I'd certainly like a guy who's a good recruiter, especially coming from holy recruiting ground like Texas(and am desperately hoping Davis in the interim has found his inner recruiting Ron Zook or the Texas fans are just flat-out wrong there)but he has a good resume for offensive production even accounting for rich Texas talent.
It may be that a year away from coaching revitalizes him, and that coupled with being around one of the real nice guys in college football makes him along with maybe feeling he needs some vindication wants to recruit the hell out of Texas. Reading the Haas article I like the idea that this guy is still looking around at other offensive systems. That tells me he's still interested in improving as a coach and isn't content with resting on just his old ways of doing things. I would have preferred Tom Moore, even if that meant just a couple of years of him, but this guy seems to fit Iowa, and while his play calling will likely be predictable it probably won't be in the same way that KOK's was.
I'm almost cautiously optimistic about him, but not quite there yet. There's always spring practices.