Are we talking about the ability to fly by sole reference to instruments or are we talking about about flying IFR? A pilot who is well versed and well trained to fly on instruments is surely just as good at doing that if he has an IMCR or an IR. There are many pilots who may have no desire for an IR who nevertheless are very good at at IMC flying. Please do not look down on those who do not aspire to an IR and also do not assume the IR make for a better IMC pilot. I have met the odd IR pilot who just simply could not cope with flying IMC outside his/her own world of controlled airspace, radar vectors and STAR procedures etc. any more than I could cope with some of that without further training.