Sorry, I don’t follow this argument. Firstly, as you have already alluded most GA operates outside of CAS. Their typical missions will continue to between small airports, which if they have any commercial traffic at all will be limited in number.
Fuji, You need to make your mind up, either you want access to the airways or you don't..... If you don't then the IMCR remains a viable option and we have to look at what needs to be done to improve the standard and give fair credit to those who want to go on and do the full IR.
SteveiB1, the problem with trying to restrict an IR to day only is that you start to become a liability to ATC if you hit weather, wind or ATC delays and end up arriving after dark. A good example, last week I flew IFR to Cannes, hit much stronger winds than forecast and as a result ended up nearly an hour later than I expected well into dark. I had to divert to Nice on a procedural arrival followed by vectors to the ILS that took another 40mins. What would I have done if I had a Day only IR? I flew in over the ALPS at FL150 so any diversion would still have seen me arriving well after dark. Sometimes we just have to resign ourselves that we have limitations rather than trying to change the rules. I would love to have been an Olympic sprinter.........