You are ignoring the point. The offense run during the playoffs, against the very best teams in the nation, was very different from the 2015 offense. He was successful against the best in 2014. He was much less successful against the soft part of OSU's 2015 schedule because the offensive schemes were different. Trust me on this one, I watched the games, all of them.
Please don't read this as a glowing recommendation for the kid. I don't know whether he'll be successful, but, I know how different the 2014 championship scheme was compared to 2015. One suited his abilities & the other did not.