For many the EOS 5D Mark IV was to be the resurrection of the DSLR camera as a video professional’s tool of choice. However just looking at the reactions online and the spec sheet itself it looks like Canon missed the mark by a mile in this aspect. Several camera shortcomings like the codec, crop factor in 4k and lower resolution for higher frame rates come to mind.
The over four year wait which was about the same between the Mark II and Mark III models is extremely long for a product class that needs to evolve constantly in order to remain competitive. With Sony and Panasonic doing real innovation in the video space in a much smaller time frame usually 18 months, Canon needed a product that could withstand to scrutiny for a few years.