Interested? Sure, once I've gone full-frame, and after I've seen some reviews, and once the lens is on rebate for $200 off, then we'll talk. For the price, IQ needs to be better than the 70-200 IS II (or at least match). If Canon includes this lens as a kit with the successor to the 5D2, then the chances of my jumping on board would increase quite a bit.
Then again, I tend to prefer larger aperture primes once the focal drops under 100mm, so what I really want to see is a 35mm f/1.4L II. It would be awesome to have a weather-sealed, auto-focusing 35mm lens with smooth bokeh and kickbutt across the frame IQ wide open. I mean, hey, it's okay to dream, right?