As the quote from Kulick said yesterday, Iowa was searching for identity early in season. They found their identity over the last 2 WEEKS. The stuff they were doing against OSU they did against Minn as well. The difference was vs. Minn they dropped balls, had penalties, and missed blocking assignments. Also, Minn was more aggressive with blitz, and in the 2nd half it was clear that Minn could do nothing against Iowa D so the Iowa O played conservatively.
We also can't lose sight of just how much OSU screwed up assignments, and not due to any trickeration or tendency breaking. They just weren't prepared for plays that have been Iowa's bread and butter all year long. On the flip side, Iowa nailed their assignments across the board.
So any change really started taking place a few weeks before, and in reality it has been a gradual progression throughout the season. Iowa was very successful last year running even when everyone knew it was coming. For whatever reason, they have not been able to exert their will to the same extent this year (probably combination of losing Meyers/Boetger/Butler, new OL coach, Stanley not being afforded the same respect by opposing D's that Beathard was given). Should this progression have been more rapid? Probably, but it is hard to take that leap of faith in your 1st year QB and de-emphasize what has been your recent strength (OL and Wadley). Maybe a different staff would have seen the writing on the wall sooner. Then again, maybe a different staff would not be able to create a culture that leads to 100 young men believing they can route a top 10 team, and then putting in the work to do just that.