He's played a few stuttering introverts, but since Bruce Banner is hardly one of those I wouldn't say that was a top notch point. Sure, he can flip the switch and go haywire, but since the Hulk sections will most probably be CGI, I can't quite see where your link is. Ed Norton's relatability is always something that has bothered me in films; in Fight Club that is overcome by the narration lifting almost directly from the page, in American History X it's his redemption that gives him relatability, but other times his tone is simply cocky. Granted, that's only part of a few characters he has played, but I'm not sure he has enough charisma to fill the screen alongside mass special effects.
Ford was always a dab hand at relatability with the audience and survivng in a cacophony of SFX, and he isn't bad at constant vigil and self control. He might not have some of Ed Norton's laconic tones, but really, he is Harrison Ford. That suggestion was just hyperbole though.
I still think there would be better leads and even better character actors who could play Bruce Banner.