The fps limit doesn't apply to the 45mp R5 as it is just as fast as the 7D2. So again, a 45mp R5 would be a better choice than a crop RF. Also, if they make an RF version of the 7D2 it is not going to be cheap. The only thing that will be cheap is if they make a RF version of the Rebel/xxD, and if that is the case they will be sure to gimp it some way so that is undesirable to pros.
Re: 5DsR I don't find the fps limiting for my use cases. I had a 7D2 and found while the 10fps was neat 99.9% of the time it just resulted in more duplicates to go through I didn't need. While capability for 10fps is better, 5fps has not created any barrier for me - and that is probably the case for most people TBH. On the other hand, having two identical 51MP bodies makes lens selection and change coordination a lot easier, with the knowledge that either body can be the equivalent of a highly detailed FF or a long reach crop.
So make up your mind. Is it the cheap 5Ds (which are all gone now, and have been for a while, by the way) or the $3,900 R5?
Either way you're still thinking that because something might be a better choice for
you and
your use cases that makes it a better choice for everyone. I'm not saying an R7 would be better for you. I'm saying it would be better for me and those who shoot the same things I shoot.
As we've already said, cropping the 45 MP R5 to APS-C only gives 17 MP at a time when a very good 32 MP APS-C sensor already exists in Canon's catalog.
20 MP APS-C was exceptional when the 22 MP 5D Mark III was the highest resolution FF body in the catalog. But it's not 2014 any more.
And for the dozenth or so time, it's not the low cost of the 7D Mark II (which admittedly was very nice) that made it so attractive. It was not having to buy a $6,100 EF 300mm f/2.8 L IS II instead of being able to use lenses I already have that makes it such a great solution.
As to the "identical body" thing: the 5D Mark III, 5D Mark IV, and 7D Mark II can all be set up to operate identically. Yes, there are some options one offers that the other do not. But the buttons are in the same places and there are enough of the same menu options in each of them to set up a very usable camera with the same options selected for all three. I'd expect that an R7 would be equally similar to the R6 and R5 in that respect.