Absolutely spot on.
Great points IMO.
(1) Yes - and target the new flight simmers. e.g. the many who I assume will migrate from X-Box after the MSFS 2020 X-Box release. They'll be buying new Win 10 machines.
(2) True. And surely the Janes line proved there is a market for that level of play balance?
(3) I was super impressed with the mods at http://yankeeairpirate.net/
(4) IMO, if he added
Better lighting/atmospherics
Elevation data - the billiard board terrain doesn't excite folk anymore
More structures
Upgrade the skin res (optional)
and kept all the content the same = a winner!
To illustrate 1,2 and 3, check out this screen from Project Wingman, made with the Unreal engine. This is what people expect these days.