As a long-retired A320 driver, would love to read all these pages, but have a bitch in whelp. So just a few thoughts.
Is this successful ditching unprecedented for a large jet with wing-pylon-mounted engines? Ironic it should be so soon after the Perpignan (sea) accident.
Assuming double-engine failure, an attempt to start the APU would be a win-only policy, and I guess there would have been time. This would have secured decent hydraulics for the slats/flaps, and full FBW in Normal Law. So the aeroplane could have been taken to a very high alpha once it had been flared near the water. However, I can't remember the recommended ditching pitch-angle (deck angle). It may be only about 7 - 10 degrees.
Did some of the pax evacuate without their life jackets? If so, it underlines the lack of interest of so many in the briefing and flight-safety cards. I guess the first evacuees could have been out of their over-wing exits unmonitored by the cabin crew? A320 has inflating dual-lane overwing slides, as the gear is taller than the B737. There is, however, a way of de-activating them if required, before you open the window. Not something an ordinary passenger would know about, and there were only 3 flight attendants, I hear. Don't see the wing slides in the photos.
The same BBC-TV aviation pundit that someone quotes above also opined that the aircraft needs BOTH engines operating to climb after take-off... Where do they get these people?
Why did the boat (rescue) crew lift one wing out of the water, and did they think and manage to close the forward door on the other side before doing so?
The A320 is a fairly tough aeroplane, apparently. Wing pylons on all types are designed to fail on ditching, without damaging the wing structure.
Forgive me if I'm repeating previously-posted comments.
Regards, Chris