The interesting thing about the R series is pricing. If Canon (and Nikon) really want people to jump into this system pricing would be aggressive. That, of course, would anger people who recently bought new EF FF equipment. Still, think about it: B&H has the EF 50mm f1.2 at list price: US$1,449.00. The list price of the R 50mm F1.2 is $2,229. If Canon really wanted people to run to this system, price is one way to do it. Perhaps, as a new system, Canon doesn't want initially to be overwhelmed. Or, as I say, it doesn't want to anger EF owners. Still, it's interesting.
On the other hand, note that the list price of the new R camera is US$2,229. That's only $300 more than the list price of the 6D2. For that $300 you get more megapixels in the sensor and a huge number more AF points. On the other hand, it seems from the official brochure (
https://store.canon.com.au/media/attachments/EOS_R_Camera_Brochure.pdf) you only get 3 frames per second in continuous servo mode. For me that's a big negative, and one I'll bet will be a deal-breaker for many.
UPDATE: I just checked with DPReview, which says the camera gets 5fps with AF tracking (which compares to 6.5 FPS on the 6D2) or
3 fps in the higher-precision 'tracking priority' mode.