Again, I'm not trying to make the case that ISUs offense is terrible, or was terrible against KU. Nor do I have any concerns about ISUs offense under MC moving forward. I think it's going to keep getting better, and has been good considering ISUs talent and strong defense. However, I disagree with some of the (mostly national) people mentioning MC while referencing the "McVay factor," as in NFL teams taking a risk on a young guy that's an offensive innovator. I think MC is a great coach and I hope he's here forever, but his strength has been more as the CEO rather than as a technical offensive guru to this point.
As for your point on the ISU scoring vs. what's given up, I don't think an aggregate is a very good way to look at it, and I think including FCS and maybe even G5 is a little misleading. Either way, any metric you use shows that ISU has been largely carried by defense, and the offense has not been all that great despite a historic level of breaking tackles and ball security. Not that coaches have no impact on those two factors, but I think Chuck Bruce deserves most of the credit there.