I do wonder though... while I think the impact of diffraction is generally overstated, I don't see much benefit to mounting f/11 lenses on sensors of the sort of pixel size/density the 7D folk seem to want. I know AlanF has done some tests on this with the 90D, but obviously you can't mount the RF lenses on that. Would they be getting much more reach? It's diminishing returns, I feel a bit of wishful thinking might be involved if that's what people are hoping for.
Maybe the 800mm will be "over the edge". I don't know. Will definitely try it myself ! But if I want 35mm-equivalent reach of 800mm, at approx. the
same weight as the RF800/11 lens, I can get the RF100-500 as a
much more versatile lens on an APS-C body:
1) Equivalent to 160-800mm fullframe zoom
2) Probably faster AF than the RF800
3) Much much better minimum focusing distance
4) Full sensor AF-coverage (vs. only center-part with RF800 on fullframe body)
5) f7.1 APS-C should also be comparable with f11 on fullframe I guess?
PS. Personally I don't only want R7 for "reach". I want it because it (I assume) is high-end and fast tool I can afford, and because the
all-purpose kit I want will be much more lightweight with the lenses I would get (or EF-S lenses I already have) for an APC-C camera,
including wideangle lenses. But reach for wildlife and sport/action is definitely also a good thing.