Humble perspective
I first got an IMC rating 10 years ago and renewed it only once since.
Although I regret feeling this way, I really do, I can see some sense in the rating being retired...certainly given my experience anyway.
I really enjoyed doing the training and it definately does sharpen your skills, but I never really felt sufficient safe to fly IMC solo despite being technically able to do so. I did some ILS approaches in cloud after getting the rating, but I never felt sufficiently equipped to undertake regular IMC trips in bad weather. The risk/benefit balance was never positive. In addition I was told numerous times in conversations with experienced aviators that the rating is nothing more that a "get out of trouble" rating and is seen as such by the CAA.
In addition, the flying schools I went to, although excellent in training, left me cold and dry in terms of encouraging/helping me to become a regular IMC aviator. In fact, PPL IMC trips were discretely discouraged in their hire fleet.
Having started the ATPL theory and becoming increasingly aware of how difficult the full IR is, it does leave me wondering just maybe the IMC could be guilty of tempting insufficiently trained/safe inexeperienced pilots into very difficult situations. If I remember correctly (pls correct me otherwise), a newly qualified PPL can go straight into an IMC rating and being flying around in marginal conditions with less than 60hrs under their belt. That does seem worrying.
Its an expensive rating to acquire and to maintain. If you're that commited to instrument flight, and can afford to maintain the skill, surely a full IR is a more appropriate?
Ultimately, I do harbour a degree of dissapointment at the state of the UK private flying scene, which does feed this particular perspective, so I do apologise if I seem negative. It's a shame there isn't a stronger GA club scene here as there is in France/US for example (and less congested airspace too!).
I'm not saying PPL holders should not fly on instruments, I am just of the view that the existing rating probably does need refining in some way. As a training course in its own right it's a great thing...but it is tempting to subscribe to the view that all pilots flying in IMC should be trained to the same level regardless of the number of people sitting inside their aeroplane.
However, my mind is still open on this and would be very interested in continuing to read other perspectives.