Onan - Shame on you!
MarkD - for years most engineers have known that rearward-facing seats are safer. It works on trains. But as many other posters said, most people don't want to face backwards. Me, I'm quite happy to, but I don't think you could sell it to the vast majority.
And as for ditching, well surely opening the doors all depends on how well the fuselage stands up to the impact. I wonder how much impact would distort the fuselage and prevent doors being opened?