Ross just posted this in a FanShot earlier today, but I think it's worth a closer look. Bama Hawkeye, who is a fine fellow and a certified Friend Of The Pants, posited that it may be time for Iowa to start transitioning to a 3-4 defense. Bama's reasoning is that Iowa has a glut of talented linebackers (true), a dearth of talented linemen (also true), and lots of opponents who don't run I-formations or run much between the tackles anyway so what's the damn point (also also true).
And it's still a terrible idea.
First off, yes, Iowa's defense underperformed late in games last year. That was primarily a function of a lack of depth--the front four's backups weren't very good, as was the case in the secondary, and as for the linebackers, the backups all became starters. Seven different players started at linebacker over the course of the year (though it might be eight; I could have sworn Ross Peterson started a game, and I only see 38 starts listed between the seven men), and the rotations got so convoluted during the second half of the season that for the bowl game, James Morris started next to two players that had originally been ahead of him on the depth chart at MLB: Troy Johnson and Jeff Tarpinian. So in a linebacker-intensive defense like Iowa's, that lack of stability clearly hampered the cause down the stretch. One would hope that Iowa doesn't experience those types of problems again, and if it does, well, there isn't a scheme in the world that can make up for a defense plain running out of bodies.
The bigger issue, though, is that switching defenses is a huge undertaking. This isn't just a matter of "Hey Shane DiBona you go in and Mike Daniels you go out okay done"; there are pretty specific types of players you need for a 3-4 and for a 4-3, and the overlap isn't that great. You want Iowa to run a 3-4? Who are the space eaters in the middle? Carl Davis is 295 pounds, sure, but he's the only defensive lineman over 277 pounds. And there's precisely zero indication that he's already ready for the big time already.
Similarly, Broderick Binns becomes less useful. He's too small to play DE in a 3-4, and to our knowledge he has only practiced with his hand down at the snap. Binns is actually not bad at dropping into a short zone and using his arms to create disruption for quarterbacks, but a 3-4 rush LB needs to be able to do more than rush the QB and cover the flat occasionally. He needs to be a, y'know, linebacker.
Speaking more generally, the reason you rarely see a major defensive overhaul happen in college football is that unlike the pros, where massive personnel shifts can be (and routinely are) made, a college team has to recruit its athletes, so getting the right players in the right spots and getting them a workable level of experience takes years to undertake. Usually, that transition is pretty rough. Look at how Michigan's defense struggled under Rich Rodriguez, after all. Sure, Greg Robinson is a putz, but the personnel was just never there for Michigan, because they had to recruit it all over again. Now if Brady Hoke scraps the plans RichRod and Gerg had in place, guess what? Back to Square 1! There isn't much success that comes from having a defense at Square 1.
Last, there's no indication that Norm Parker has any desire to coach a 3-4, and let's be honest: Norm Parker doesn't strike us as the kind of guy who does a whole lot of things that he doesn't want to do. Norm has his system, and it works. We don't know--not one little bit--that a 3-4 would be at all more effective than the products Norm and Ferentz have put out on a yearly basis for Iowa.
Is the 3-4 the way of the future? Perhaps. One could certainly argue that it's more effective against an offense like a spread option (or any system that's designed to attack the perimeter of the defense, really), so to assert that Iowa should never run it would be to engage in the type of blind fandom that most closely resembles Romain Rolland's nationalist hypocrisy (sports rivalries also fall under this definition, but shhhhhh!). If Iowa does move to a 3-4, though, it'll have to be part of a basically seismic shift in the program's approach to the game, and I don't expect that to happen until Norm Parker and Kirk Ferentz are no longer coaching this team. Until that day comes, gimme four down linemen and three linebackers every down, every week, every year, baby.