In you opinion... why do you think it's fantasy to assume the video would look equal? Because one camera is bigger and purpose built? Who cares, that's irrelevant these days. Besides Panasonic even stated that they put allot of work into the video on the GH2 to ensure a proper motion picture. If they are both shooting off of relatively similar chips with the exact same codec how will one look any better? The only advantage is the lack of aliasing in the AF-100 dues to a smaller pixel count... which would make sense that it has a more noisy image, since it's not being down-sampled as much as an SLR image.
This, of course, is all speculation on my part as well. But IMO, it's even more of a fantasy to think the image with the same codec from the same sized chips is going to look vastly better. The real fantasy I think people are holding onto these days is "only big cameras can make big images". Example? Epic vs. Sony F35. End of discussion.
And yes, bigger pixels do mean less noise... but so does many smaller pixels down-sampled. I think the latter also has the better picture in the long run.