1920*3=5760 which is exactly what 5D3 got.
That would be a 2:1 aspect ratio, not much love here. And It would require odd blending/skipping patterns to capture standard video. Not much love either.
The first fitting, in tradition of the 5760px of the 5D3, resolution would be 1920*2*2 - to get full RGB for 4k-video and 39.3MP stills. going for the slightly larger 4096 flavor would net you 44.7MP. Current OTS cores can handle that resolution up to about 30fps; in a dual config. that should work even with continuous AF. no line skipping also implies less moire and less noise at higher ISOs. Dual photodiodes allow for higher low ISO DR. Who could argue against such a machine?
Yes, 39.3MP would be nice for 3840*2 and 1920*2*2 (or 1920*2 crop mode). I just have this feeling, that Canon wants to bring something exclusive to the market. Something the competition can't match any time soon.