Note that the use of HDMI2.0 ports (both the R5 and the Ninja V+ means that only 10 bit 8k can be recorded externally. 12 bit for internal recording. Why Canon can't record 4k/120 externally is puzzling and should be possible if the bit depth is lowered.
Recording externally is one piece in the puzzle but you also have to store it on hard disks and even if the price drops over time, it is still an investment to consider.
I would suggest that a 25% increase in the 8k raw recording times by tweaking the firmware is a pretty good increase. It might not be the doubling or tripling of the time limits that you are looking for but it is a major improvement a month after release... and it was released with full disclosure up front of its limitations. People could not buy the camera without knowing the limitations and there still is a big backlog on order.
Standard 4K is still unlimited even when 4KHQ,4k/120 and 8K modes are not available. Not sure why this is not mentioned when talking about overheating.
Surely external recorders are cheaper than the large CFe cards that would be needed for long recording times.
A more interesting point is their press release about the next firmware version with lower bitrates, clog3 and HD/120p. Hopefully, 8k raw and 4k/120 could be recorded externally and without the heat generation of internal cards, it could mean longer record times again.
The joystick is a standard one and not the one from the 1DXIII (as much as it would have been great). Blue circle is depth of view preview button but it will probably be assignable. The yellow port is for the remote cable release, Both similar to the 5Div layout.
8K30 needs ~45mp sensor so that fits (for 16:9). 4k60 already exists in the 1DXiii so the digic8 can handle the bandwidth. 4k30 (maybe 60) could be uncropped (oversampled). 4k120 may be cropped. It would be unlikely that dual pixel AF is possible for 8K but people using it would normally manually focus. The initial rumour had 8k30 raw (no oversampling) which makes some sense for external recording as the requirements for large CXExpress cards would be very expensive. Managing heat will be the challenge
1DXiii only has 20mp sensor so it can't do 8k by definition. 4k120 is another question though (firmware upgrade?)
Canon has limited their video capability for the EOS R/RP but it is likely that processing power/bandwidth was the limitation. The cinema range has a different form factor and the R5 wouldn't compete on that basis but would be a great B cam.
Canon needs to lead and the R5 will leapfrog the competition in the mirrorless segment but the price is a big question mark. Let's hope the rumours are accurate... it can only be good for the industry and Canon in general :-)