Canon should of taken the money from my hand with the EOS R, but they didn't because of all its problems. Instead went with a fuji XT3 as a B cam / gimbal cam. Its an amazing camera for the price. You guys need to get over the full frame fetish because it just doesn't matter, in fact its just plain harder to shoot when it comes to video. reality is APSC / S35 is a rather ideal compromise between sensor size, DoF, DR and everything else you care about. In practical production, you're going to shoot FF a stop more closed down to get some margin of focus in DoF which means you are matching the look of S35, but with more light or turning the ISO up a stop. So same difference, just harder. C300-2 is a S35 size sensor btw...
canon's lack of a C300-3 or C400 at NAB was no doubt due to lack of a R mount. I'm sure they had it ready with a EF mount, but went back to redesign the body with a R mount to sell R glass, or LPL. Getting an internal ND wheel into a body like that is gonna be a challenge. They want to move away from EF as fast as they can now to sell us new glass. bad move, no wonder their booth was pretty empty even on mon.
while still camera bodies are nice for small size when thats important, lack of solid audio in some cameras, lack of XLR, SDI, TC I/O, not shoulder mount friendly, lack of good internal / on board batteries, enough buttons and knobs for important functions, not so easy to work with large lenses w/o lots of rigging, and adding on all the other gack means cinema camera bodies still have a lot of value for most folks.