Brand new image sensor (as Nikon D5, although the quality might be questionable)
Brand new autofocus (as Nikon D5, less points, but very probably larger frame coverage)
New metering sensor with IR sensitivity (more pixels than D5, does D5's metering sensor have IR sensitivity?)
14 (16 fps) burst (2 fps faster thank D5)
Touch screen (similar to Nikon D5 but less resolution)
Fairly larger buffer (similar to D5)
Bigger viewfinder than D5
New battery (with hopefully longer life as D5)
4K/60 fps, 1080p/120 fps video (far better than D5)
Built-in *** (better than D5)
Price 5999 USD lower than D5
In almost every aspect is 1DX2 similar to D5 or even better. Nothing revolutionary, but so doesn't Nikon D5.