I not only sometimes shot action/sequences with 100 ISO, but my 7DII I have permanently set to highest framerate. When not shooting action/sequences, I'm usually bracketing where it too find it practical/best to shot at high framerate.But you usually don't shoot high FPS scenes at ISO 100. So you're loosing DR anyway, so that slightly reduced Bitrate should not translate to a real world disadvantage, right?
Unless you also set up a studio comparison with identical lighting conditions and settings to make your personal observations, any differences you see are hard to blame on the resolution differences.
I have 6 years experience with the 7DII. Never seen that kind of "dots" with my 7DII. I was shooting several sessions with the 90D over a couple of weeks, and the dots were consistent in high iso shots from all sessions. I don't need a studio-comparison on top of that to feel comfortable about making a conclusion for my kind of use. However as Michael points out, using other RAW conversion software than Adobe might make a difference. I don't know.As for white dots, that sounds odd. That's a type of noise I would expect for long exposures, or really hot conditions. As Michael pointed out, it may also be a technical difference.
For me it's also a matter of price - and size+weight of normal and wideangle zooms. I'm never going to buy a camera priced like an R5, and don't want a bigger/heavier "casual/everyday kit" to carry around than I have now.Anyway, as I see it, an R7 only makes sense if it can make the most out of long lenses. So it must have a sufficient pixel density to exceed the R5 and compete with the eventual R5's / R3 high MP FF body.