[davidmanze]

The EOS R focuses at max. aperture ... understandable in low light but with sufficient light that is suboptimal with respect to RSAs.

This data represent the current state of development.
Initial reviews shows that canon eos-r AF is sub-optimal - not in pair with sony.
Initial canon statement was - We are going to release mirrorless when we can deliver ML exereance similar to DSLR. 
At this stage canon and Nikon are behind sony and for sure not in pair with Canon/Nikon SLRs  It is marketing push instead of development pull

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Oh yeah, and the 4K is cropped for the R (which means it would work great with my EF-S 10-18mm f4.5-5.6 IS STM )

:-)
Yes you can drive your Ferrari in the city. Even more you can attach your KIA wheels to spare some cash. :-)

Now seriously

Same comments here. Canon is far behind the competition Panasonic GH 5, even the older GH 4 is beter choise, and it offer similar senoser size to Canon FF/video crop.
The old Sony 7s II is also great option.
Yes canon is making progration, they offer more than the crappy MJPG, but they are far away from the competition. Not to mention that 5 years old smartphone can take slow motion  1080p 120..180fps using H.265/H264 codec  
Yes they make progression - They discovered the articulated touchscreen. The entry level camcorders from 35 years ago had articulated flipped touchscreen. yes it was 35 years ago. well done canon

If you really are saying that filming on H264/H265 is a good thing.... means you have no idea about video. H.265/H264 are great for high compression end results, not the best for raw footage. That is why the 5D mk IV's MJPEG CODEC is so nice.
The high data rate for the EOS R (480 mpbs)with 4:2:2 10 bit is FAR superior to any smartphone, to say the least.

The GH4 doesnt offer that high data a rate 4K, the GH5s kinda does, is more expensive and will never offer FF stills.

Do you know ANY APS-C photo camera with flip out swivel screen, in-camera C-Log and capable of outputting uncompressed 10 bit 4:2:2 4K UHD through HDMI with C-log gamma applied..... And that for $2200.

Now seriously, indeed.

  I think it's worth bringing to light that your beloved 4K MJPEG codec which maybe technically better............

     ........is totally "unbeloved" by just about everybody else......

  ......and consistently flouting it as the best thing since sliced bread is falling on deaf ears in the video world......

   Nobody wants it in "their" camera......not even 5D MkIV users!