It is the offensive system right now. That is what will put ISU wrs in the NFL soon too. Butler is going to be a good NFL player. Not sure who the next one is, but it will happen again soon with the recruits you are pulling in.
Iowa is a good system for OL, TE, DL, LB, DB to get to the NFL. WR.... not so much but some have done it, just not consistently stuck on NFL rosters. If that changes then Iowa will also get those guys a chance too. Which is why most spread WRs are getting looks by NFL teams, which proves my point in what I am saying about recruits and the NFL.