The description of the R5C sounds very much like a C70 with a R5 45MP FF sensor in it. Which, in my opinion, is not very much of an upgrade of anything. Worse than the C70 in image, bigger than an R5 with no benefits except record times.Stranger things have happened. We never thought the R5 would be as amazing and feature laden before the announcement.
There is a new FF DGO, 8K sensor with 17 stops of DR rumoured for the C500S so who knows what Canon will do.
I would much rather take a this new FF DGO sensor in the rumored C500S gimped to 13-14 stops of dynamic range or something.
All we need is a FF DGO sensor in a small cinema body (c70 or smaller). If the form factor of the C70 was tweaked a bit and the screen improved that would be awesome.