Man, I'm so glad things worked out the way they did. Too bad Marvel didn't have the foresight to cast Ruffalo in TIH to begin with. I think I was always more in love with the IDEA of Norton being in TA, not necessarily because of what he did in the role. Although, I do agree scenes like his "breakdown" at the dining room table should've absolutely been incl. in the final cut. For that scene alone, I can understand Norton's disdain for Marvel.
As far as Ruffalo: he just looks like a geeky little scientist that may have something brewing inside of him. I'm glad to hear the WOM so far regarding his performance(s) are overwhelmingly positive.