VERY interesting. Something has to happen in the Canon camp!
That depends on what the D4s can do - if it just narrows the gap the pressure is more on emotional side. Even a slight edge wouldn't have much impact. And seriously surpassing the 1Dx would warrent a promotion to D5. not just the incremental s. As for video: 1080p@60 would be expected, but the 1Dc can do that too - it would require 4K with RGB readout and at a decent framerate to get folks seriously interested.
I'd say the D800 is a stronger "something has to happen"-factor