Tough choice for the staff going into next year.
Jantz has the stronger arm and is a better runner in my opinion, and early in the season he was actually a pretty accurate thrower. I'm willing to give the benefit of the doubt and say he was rusty coming back. But he does not see the field well and is too willing to throw into coverage, which leads to turnovers.
Barnett came in and was steadier early. I think he sees the field better than SJ, and doesn't force things as often, but his mechanics have deteriorated as the season went on and the turnovers persist. He has time to improve, however, and barring any significant changes over the winter I would probably put more time into developing JB than SJ if I was the coach.
A big 12 QB needs to be able to accurately assess the defense pre-snap and deliver the football to the right place with accuracy. ISU's offense will not improve a whole lot unless we find a way to deliver on this.