Mark 4 looks primed to be a big disappointment. 1DX2 is being outclassed by the D5, losing in the key areas of AF and High ISO performance. So judging by that, 5D4 will only be a marginal improvement over the 5D3, with the only real improvement (for stills) being dynamic range at lower ISO, anti flickering, slightly higher fps burst, as well as the center point rated up to -3ev. Stuff like Wifi, GPS, Touchscreen does not affect the quality of the photos in everyway... and people who shoot for billboards will stick with their 5DSR anyway so higher MP is useless.
Videographers will probably love 5D4's live view focusing and 4k, but then again these doesn't affect stills photographers.
I guess Canon didn't expect Nikon to make such an enormous leap between D4s and D5, which probably caught them by surprise. They probably thought that the 1DX is gonna sit on the throne for a while hence was only working on features and marginal upgrades. So all things considered, 5D5 and 1DX3 should be one hell of a revolutionary camera
but will Canon come out with software upgrade to competes with Nikon. although the history show no competition for this series of model but to improve the bug in it
