RC you say it was never intended that IMC rating holders PLAN to fly in IMC. My personal advice to all my IMC students and holders is that the only flight that should be undertaken in IMC is that which has been thoroughly planned.
As for getting out of trouble, if you hadn't planned to fly IMC then trying to locate your flight bag, extract the appropriate plates, work out a diversion on the hoof because your PLANNED destination doesn't have an approach etc etc etc is not conducive to maintaining controlled flight which is the only part of the IMC training which we are now apparently supposed to use.
So why not PLAN the flight, PLAN to make an approach at the other end, and then if the weather does turn to **** there are no surprises to catch you out.
I don't think this is an abuse of the rating.
As for the radar service, it was always part of the BCPL/CPL flight test that on the IMC leg you HAD to upgrade your RIS/FIS to a RAS.Are there different rules before Public Transport flights can be deemed to be complying with IFR ? - well apart from it just not being allowed single engine anyway.
Is full radar cover available on trans oceanic flights ? I'm sure it hasn't always been. Still not recommending you go IMC without a radar service but just a thought.