Two points to what you state.
1) Iowa doesn't primarily work from under center all that much anymore. At least 85% of their snaps are out of the gun. They transitioned to that from at least Beathard forward.
2) The statement that if he came to Iowa he would not be taxed mentally is completely wrong. Many fans say Iowa doesn't run a very complicated offense and is not too involved. Contrary to popular belief, actually it is, and very involved, much like an NFL style. People that know football understand this. I am not saying you don't know football, either.
The QB in Iowa's system is making a lot of reads prior to the snap. They are running a complex offense. A runner going in motion is not to trick a defender, per se, a runner goes in motion to allow the QB to gain info, such as is the defense going to be in zone or man-to-man that play. This will cut down on the QB reads. In addition, the QB's are making very technical passes depending on the situation. Back shoulder throws, fade routes, air under the ball just a bit for a certain route, zip on the ball for others. This all comes into play. Not all QB's excel at all the throws. Is KF really going to bring a QB in for one year which would have to make fit his system, again, just to get one year out of him. I don't think KF would be interested in this project for a 1 year gain, in addition, upset the QB room. Would Joey Labbas or the current #2 on the depth chart appreciate this. Coaches do not want players who have been in the system and who could be the future leaving after grooming them.
Again, Martinez would come from a completely different style than what Iowa runs with a stiff learning curve for 1 year. Is it worth revamping that skill set or risking the QB room to bring that situation into play. Those are the questions.