One R5C element that got some attention among reviewers was the fact that it appears to have two independent operating systems available, depending on whether you're using the camera to shoot video or stills. Most reviewers found this a bit janky, as it requires a reboot to switch over. DPReview's video-focused reviewer Dale Baskin disagrees in an interesting way.
Baskin notes that in the past cameras moving toward hybrid functionality would add video- or stills-related features in an add-on menu. Being a video guy, he finds himself frustrated with interfaces that throw video features into a submenu.
It is true that most R5C buyers are less likely to be amateurs – who would find the R5 perfectly suitable – and are more likely to be applying the body against actual professional work. Those people want the Cinema EOS features. For them, a five-second reboot is worth the trouble.
The implication of all this may be – contrary to almost everyone else who has commented on the interfaces – that this was more a deliberate strategy for the specific market, rather than Canon not having had adequate time to meld cinema features into the R5's “red camera” menu. We may see more cameras in the future employing both systems.
In addition to the Cinema EOS and the operating system most current Canon shooters know from its full frame offerings, it also maintains at least two others: a security camera version and the point-and-shoot camera platform that was later morphed into the EOS M platform. That is a lot of platforms to keep updating, especially when some major new features – like tracking – apply to two or three of them at a time.