I've thought for a while about this, and have decided I want the US system, with refinements. NAS tried to deliver a system that gave Dick Smith what he wanted (fly anywhere, listen to cd's and fack everybody else). It is just dumb to have ATC sitting at ATC consoles giving the same service Flight Service did 30 years ago.
Look after the big boys with positive separation. Bug-smashers let into the holes between them.
Full ATC service for IFR everywhere else, with the IFR able to opt out of separation when conditions are suitable.
Full advisory service available for VFR, on going, on request.
No idea how to do it.