I hope Canon would not pull a “Nikon” and easily announce they’re growing the 1Dx III with out giving any particulars. Inform us one thing we do not already know.
The three issues I might wish to see in a III are higher autofocus, much less of a “dust-magnet” and a quieter shutter in “silent” mode. (Though I’ve solved the shutter noise downside by shopping for the R)
The 1D x will not be a video digital camera, so do not count on any video options that may compromise it is use as a stills digital camera.