Frankly, if the R5ii has the majority of the firmware updates that users would like and a couple of HW upgrades (full HDMI 2.1 port, USB-C port to record from, new hotshoe) plus some thermal tweaks (and ability to remap the Rate button to something useful!) then it would be an excellent replacement. Dual CFe cards would be nice but not expected. Something like the 5Div vs 5Diii... reasonably better all round rather than revolutionary.
Maybe not an upgrade for current R5 users but certainly competitive in the price segment.
Perhaps the current R5 could remain in the line up at a lower price like the R6 and R6ii.
I suspect that the R5ii is nearly completed it's developement and now just needs it's production, assembly and marketing arranged. The problem Canon now has is an overstock of new mk1's. Canon aren't going to want to pimp the feature set of the Mk1 so that would then compete with the shiney new mk2 sales.
Once the Mk2 is announced, the old Mk1 has to be heavily discounted and that will eat into the sales of both the R5ii the 6Dii.
The 5Diii to 5Div was a huge jump in sensor design. Everything about that newer sensor was better, resolution, readout speed, ISO noise, DR. The mkiii was a major refresh of everything except the sensor, which was based on the older 5Dmkii.
The R5 is just a well rounded and capable camera. It's sensor design, user interface and build are already superior to the R and 5Dmkiv. It is 2 generations of camera later and there's not a lot to improve on it except some mild tweeking to the base specs to bring it in line with the newer R3/R6ii/R8 AF algorithms. I'd be suprised if Canon add these to the current R5...however...they could if they wanted to.
I'm a new entry to the world of Canon mirrorless. I've been a Canon shooter for nearly 40 years. I've rocked a pair of 5Diii's since they were launched (and I shot weddings professionally). I tried the EOS R and RP on launch and I didn't like them. I felt that the loss of the optical viewfinder and drastic changes to the AF system was worth the investment. To me the EOS R felt like a Gen 1 beta, so I decided to wait a few generations before I dipped my toe.
I bought an R8 a month back to ease me into the newer RF system and it's a remarkable camera. The stark contrast from the 5Diii, through the Eos R to the R8 (and R6ii) is a massive quantum leap in technology and AF capability. For me, it's now worth the effort to re-learn everything because the gains in the new system are so much better.
I'd like to pick up a R5 later in the year to use as my primary camera, finally selling my trusty old 5Diii onto their next owners. But for me, do I wait for a R5ii or get a mid life R5 and hope Canon honour their promise to add the newer features and AF algorithms? Ultimately, the R5 will be more camera that I would need. But it's a camera that is entering it's autum of it's production life. The AF has already been improved upon by the R3 and R6ii/R8.
