Mostly tweaks ...
#1: Stop spotting an opponent an advantage before the ball is even snapped by expecting LB's to matchup on WR. Unless you have Edds, Angerer or Nielsen speed and saavy it's an EPIC FAIL!!
#2: If you insist on LB's in coverage they better be using their advantage -- physical size and strength -- to jam the $h!+ out of the WR and throw off the route timing. If you're going to lose the coverage matchup, anyway, you can't be tentative by sitting back and allowing the WR to dictate.
#3: See #1 & #2: Knowing that most teams are more pass oriented these days, you try to gain speed by going smaller at LB with a hybrid safety / LB. Still have size for run support and a few quicker steps in pass coverage.
#4: Not saying wholesale coversion to 3-4 but you certainly need to gameplan around it more from week to week, depending on opponent and situation. This team can run the base 4-3 in it's sleep so you can always deviate for stretches at a time but still come back to it. Overall, there needs to be more changes in base alignment throughout the game and season.
Persa summed it up -- stop being so predictable and one-dimensional on defense. HELLO! At least make the opponent's scouting report a little more distracted / diluted. Make them actually have to put in some extra mental prep during the week they play Iowa, in addition to already knowing they're going to get physically punished.
#5: Since Iowa's blitz is usually impotent / gets burned, I could care less about it. Norm can pick & choose.