On the IMC front, let's try the alternate that if you want to fly in protected IMC then you need to fly within controlled airspace where everybody else is similarly equipped and there's somebody watching over you. Isn't this already available to you providing you have the appropriate equipment ?
Unfortunately at the moment lots of "airspace" is not available to certain aeroplane types, due to performance reasons, qualification reasons and equipment issues.
Personally I'd be happy with all airspace above say FL100 - FL195 being class D so you need a clearance to enter. Then people could fly from Lands End to to the top of Scotland in a straight line with an ATC clearance, VFR or IFR!