I feel like this change has less to do with the Cyclones talent level at LB (or even DL), but realization opposing coaches have learned to exploit some weaknesses in the 3-3-5 defense.
I don't feel using a 4-2-5 is that big of a change for the staff, I recall prior to Campbell and Heacock coming to ISU they used a 4-2-5 defense at Toledo. Adding a 4th DL does three things:
- It allows ISU to be more physical at the line-of-scrimmage.
- Makes it harder for opposition run game to have success running outside the tackles.
- Puts our DL in position for more one-on-one blocking at the snap and create more disruption along the line-of-scrimmage.
It should also create a more balanced run support decision for safeties like Freyler and Verdon. It always seemed our rush defense needed our safeties to be uber aggressive in run support, creating susceptibility to play-action passes down the middle.