Last year I likened this to Iowa playing chess, while many other schools are now playing high-stakes Texas hold-em.
Iowa is thinking of out-maneuvering you. They want to diagnose your strategy, devise a counter, and then count on their players to execute that counter. By the end of the game, this will hopefully win them the possession or two that makes the difference.
Many schools these days are just playing the odds. They don't worry so much about reacting to what their opponent is doing, they are just going to be ultra-aggressive and go for big plays. On defense, this equates to bringing tons of pressure. Although they will get burnt, they are counting on the positive plays (sacks, turnovers) outnumbering the big plays allowed, thus coming out on top as long as there are enough possessions. The other advantage of this is your defenders do not need to be as smart; they are not reading-and-reacting as much as just getting after it.
While many colleges have taken this approach, the pro game still strongly values players that can read, diagnose, and react. Pro QBs (at least the elite ones) are simply too good at figuring out what you are doing and knowing how to beat it. That is why pro teams value Iowa players so much.