Who cares how many megapixels the 650D will have. It's barely relevant. We're well past the point of diminishing returns. There will be plenty of megapixels. More than you can shake a stick at.
Even if the megapixel count were of interest (which it isn't), keep in mind that going from 18 to 20 mpix involves a 5% reduction of sensel size in each dimension. Or, a 20 mpix sensor gives you 5% more pixels in each direction. Barely worth mentioning.
Now, onto the relevant bit. The real question is whether the 650D will have continuous video AF. Continuous video AF will be a very useful feature to many users. If Canon manages to pull it off so it'll be a very interesting camera and it'll sell well. If not, Canon won't be keeping up to Nikon and Sony.
The other relevant bit is the DIGIC-V chip. That should yield some performance improvement.
For those wishing for a 19-point AF module - dream on. Not gonna happen.
Personally, I think that for a very large majority of the small-scale video market would reject auto-focus during video, a computer should never choose the attraction of the eye of your viewer, with stills it is diffrent, its more user controlled, but on video it pretty much has to be manual.
(unless you're really armature, then you will get terrible results anyway, a wrong focus shift is very common in video auto focus, and very noticeable and good at destroying quality)