Might it possible that this was a high speed upset? I think it doubtful that a fully stalled A330 would descend at a much greater rate than 6,000 ft per minute. There is, after all, still some lift being generated even at quite low IAS. The speculated rates of descent in the order of 20,000 fpm are only achievable in steep descent attitudes at high subsonic Mach numbers. The photographs of the left wing section show that a large section of the outboard upper wing surface is missing and broken wing spars can be clearly seen. This kind of damage is often seen when a wing is overstressed in a high speed dive recovery. Of course, such damage might have occured at impact, but it would be interesting to know if those missing outboard wing sections are found with the main wreckage, elsewhere, or not at all.