Yes, with Johnson it was mor mental ... he's like Losman in that while physically gifted, the game is too fast for them. They can't see the field and make decisions fast enough.
Flutie, it was his lack of arm strngth. He was able to compensate for his size, but he didn't have the arm strength at he end to make plays. Once teams took his legs away by keeping him in the pocket, he was done.