I'm not trying to get contentious with you. I'd really like to know how old you are and how far back you go with ND football. My guess is that you didn't watch Theismann play. At least, in college that is. If you did, let me know.
The truth is, he was a much more athletic qb than Montana. In fact, there would be only a few qbs at ND in the discussion of being more athletic. Theismann was faster and more agile, so, a better runner. He had a much stronger arm than Joe Montana did. Before Theismann became the full time qb with the Redskins, he was their punt returner. That's indicative of how atheletic he was.
Montana had the ability to move around on the field pretty well. Heck, I even remember him being a pretty good basketball player, but he was NOT as athletic as Theismann was on the field.