I may be missing something obvious...
As pointed out by several posters, the state of the wreckage (and body parts) as shown on photos released so far and/or described fairly conclusively indicates that the aircraft hit the water in one piece at a very high speed in an aerodynamically clean configuration.
At those speeds any loss of a major structural component would immediately cause an upset and rapid disintegration in air, and speed of individual components/bodies would then quickly decay due to aerodynamic drag, with little further damage on hitting the water.