In an ideal world everyone flying in IMC outside CAS would be getting a RAS. Unfortunately, regardless of the rating (IMC or IR) and regardless of whether or not you have filed a flight plan there will be occasions when you have to descend through cloud in the open FIR without a radar service. If that becomes illegal then the UK will either have to dramatically increase radar coverage and ATC staffing levels (Hmmm I doubt it with PPP) or a major amount of flying will no longer take place.
The statistics show that colliding with another aircraft while IMC is far less likely than CFIT. Off the top of my head I can't think of a collision between two aircraft in IMC in the UK (Apart from a few I have read about during the second world war).
It can be a very emotive issue, mainly because the pilot does not (is not) in control of his or her destiny, but there have been many more fatalities as a result of landing accidents/fuel starvation/CFIT/mechanical problems/loss of control/mid airs in VMC/medical problems etc. etc.
That said, common sense would strongly suggest that you don't practice holds in IMC at a VOR in a busy area without a RAS.