From a pilots point of view its when it gets VMC that issues arise not IMC without radar.
IMC everyone is usually a pro or know what they are doing. And all will be talking to someone and have a transponder.
Its when its VMC that all the puddle jumpers are out flying VFR through the instrument approaches that things can get abit close for comfort.
The only two close calls I have had have been under a radar service and one of them was inside controlled airspace and in VMC.
Banging around the highlands of scotland under a procedural service or under radar cover with so many qualifiers we might as well have had a basic service not a problem. And when your VMC personally I always prefered to go VFR because then it meant we had two pairs of eyes outside and it allowed the procedural controller more scope for shifting traffic and there was no confusion about who was doing the seperation.