What about a 5D IV replacement? When do you expect that and what kind of feature?Here is my prediction. 1DX3 in spring of 2020 for the Olympics. 1D equivalent in beta test for olympics to tweak software for fall 2020 release.
I have a 1DX2 and I can see room for some improvement which I think Canon will do for the 1DX3. USB-C, 4K 10bit output via HDMI, bump to 22-24mp (likely 24 since the a9 is 24), clog. I would love to see built in wifi but I do know the reasons why its on a separate dongle. Would also love to see both slots to be the same card. I don't really see a need for more FPS but its always an arms race so I would probably expect a 2fps increase. I just don't see Canon having the tech to put all of this in a mirrorless camera just yet unless they have an ace up their sleeve.