Dave W - good article IMHO. And I do wear a jacket when crossing the channel.
The thing which I don't go for is a survival suit. Apart from a certain quantity of seriously dedicated anoraks who inhabit the pilot forums - and most of whom fly either alone or with similar anoraks - virtually nobody is going to wear a drysuit on what is supposed to be a pleasant trip abroad.
Is there any data on average rescue time? The point is that you can bank on being dead within a couple of hours in the water. The gliding time doesn't cut much into that - say 20mins from FL150, and far less for the vast majority of pilots who fly VFR OCAS.
No matter how one looks at this, a raft is the only meaningful escape route.