I'm not sure I care what EASA do or say, because at the end of the day there is a limit to how much they can actually do about what goes on in the UK under the CAA.
The practice is that anybody can fly any way they like in UK Class G, under "VFR". Or abroad for that matter. Enroute, there is no way this can ever be enforced.
The major immediate drawback of killing the IMCR will be that one will not be able to land on an instrument approach in real IMC - short of declaring a mayday. This will encourage DIY approaches; these may be made illegal but this is unenforceable.
The slightly lesser drawback will be that one will not be able to depart from an airfield in CAS (e.g. Bournemouth) if the conditions are sub VFR - this varies but usually means cloudbase below 1200-1500ft or so. I believe ICAO says something like 1500ft. Currently, it is normal practice to depart from a Class G airport as "VFR" under practicaly any conditions so long as the vis is not quite zero, and I guess this will continue. At non-ATC airfields this cannot be stopped anyway.
The longer term problem is that IMCR training will obviously have to cease and, with the passage of time, the number of pilots who will be able to safely fly using "imaginative VFR" will reduce. Eventually, there will be just a few old hands left, plus some current IR pilots, plus some cowboys. This is what they have in the rest of Europe, but most of the rest of Europe has very little GA activity anyway.