What I would be excited about in a 650D...apart from the touchscreen capability that has already been leaked...would be the Dig!c5 and if it has the ability to do the lens correction that the 5d3 has. Chromatic abberation, distortion, as well as the 600D's vignetting ("peripheral illumination") correction. And could do so in video mode too. That would make all my EF-S lenses worth more just by buying the body.
And since the Micro-4/3rds cameras have this functionality, Canon would want to add it to stay relevant. I don't know the details of how it works, but if it could be just stored as a starting point when editing RAW stills, so much the better.
Also streaming full-res video out the mini HDMI port would be terrific. The 600D had 3x-10x digital zoom (and the 3X form eliminated the line-skipping moire problem!) on the video, which broke new ground. So 1080p at 60fps? Sure why not that too...and for the skateboard shooter the smaller body would be exactly what they'd want.
There's no reason why the 650D couldn't lead the line in some ways technologically, even if that makes the more expensive bodies seem less-featured. Because the Rebel line is competing against Sony and Panasonic and Samsung, who have bells and whistles on their side. Canon has glass.