I think your right about opinions varying. I think the new system the RAF mountain rescue has developed is that they recognise that most victims on UK mountains are not completely wetted through and that on balance the clothing the casaulty is wearing will help in reducing the heat loss in addition to the Blizzard Survival bag being employed. (I suspect most casualties are generally winter casualties who generally wear good to high specification wind and waterproof breathable clothing) Further unnecessary cooling when removing the clothing would be painful (due to the windchill) and unnecessary timely for the casualty when they are now realistically within a few hours away from Hospital Treatment. This does make sense.

The casualty who has been recovered from the water will be completely wetted though (unless in a dry suit) and in this case will be out of the wind i.e inside the covered life raft. Recovery of the casualty by SAR may take many days. Getting the hypothermia casualty out of the wet clothing as soon as physically possible and into dry insulating clothing and then the Blizzard Tube would dramatically reduce the heat loss from the casualty.

The new Hypothermia Prevention and Management Kit™ (HPMK NSN# 6515-01-532-8056) looks good. Again the chemical heatpack maybe a no go for the liferaft application and maybe to bulky and heavy for this application. There appears to be no easy answers for this problem. Crew survival training looks likely to be a very important factor.