I would like to see Canon do like they did with many EFS lenses. There are some very sharp ones but inexpensive (10-18mm) and this could be translated into the RF mount. Most of us do not need the built like a tank lens just a good quality optically. Take out the IS once the IBIS is available in all the lenses that do not fully benefit from IS and IBIS is just fine. I would then like to see the lenses come down substantially in size and weight. Look at the old FD lenses for size inspiration, the FD 80-200mm is petite compared to the EF equivalent today. I have no problem with f4 lenses as we have insanely high ISOs available now. How did we ever survive with Kodachrome 64 and the slow lenses of the same period? Great shots were made then through real skill and talent.
Bottom line I would like smaller very sharp not super large aperture lenses to match the RF mount.
I can't help wondering if the evolution of cameras is going the way of cars ... where the price remains constant, whilst the features just keep getting better and better ...
or
the evolution of pocket calculators where they ran out of features and the price just went down and down
Obviously we want great IQ, great subject isolation/bokeh, great ease of use, and most of us would prefer small and lightweight too ...
How close are we to the point of diminishing returns ?
If the evolution of the mobile phone camera market is anything to do by then I think we are getting pretty close.
I am no optical technician, but I assume that the RF lens mount genuinely is better, although I for one can still remember IBM bringing out "Microchannel Architecture" in their PS/2 range ... which was driven far more by commercial objectives than technological gain ...
Is the RF lens just another attempt at a manufacturer to hold on to its commercial lead ... or does it represent improve the value proposition ...
I'm not in a position to judge who on this forum is correct from a technical perspective, but market forces will prevail eventually ...
Personally, I won't be making the very expensive shift from my 5D Mark iv and EF lenses to any mirrorless solution until I feel I'm getting better considerably better value for money than what I've currently got ...
As to whether the RF mount is really so much better ... well, if it is then surely all the camera manufacturers will be coming up with something similar as the science is now very well understood isn't it ?