Canon is one of the relatively few manufacturers that develops its own sensors. This means that they're in a great position to create new sensors with new capabilities, and that's just what they've done with their new 35mm Full Frame CMOS sensor for video capture
While it's tempting to think that with the Magic Lantern EOS raw hack out in the open that normal, compressed video will never be good enough again, that's taking far too strict a line on it. The fact is that the conventional video output from cameras like the EOS 5D MK III is very good indeed with the exception of certain well-known issues like moire and rolling shutter
The Canon 1DC is a curious camera. Based on a top-end DSLR design, with essentially only some additional firmware it becomes a 4K camcorder as well. But where does it fit into the increasingly complex matrix of options around high res, high dynamic range (i.e. RAW) devices that are available today at approximately affordable prices?