Malaysia has posted their analysis of MH370 debris - including structural notes on how the aircraft pieces were separated from the aircraft.
http://www.mh370.gov.my/phocadownloa...n%20300417.pdf
None of the debris had been crushed or punctured during separation. A vertical tail piece suffered damage consistent with an overload of dynamic air pressure. A wing piece was pulled and twisted off. All other pieces were separated by being simply pulled from the aircraft.
The report itself provides analysis of each piece of debris, but provides no summary conclusions.
There is one piece, a plastic frame to a back-of-seat video screen which non-Malaysian analyst claim is more consistent with being torn from the seat by water flow than by the force of air flow.
Overall, it is 100% consistent with the aircraft breaking up in uncontrolled flight. I particularly noted bending damage to a vertical tail section.
Easy to imagine continued rapid acceleration downward with small sections of the craft tearing free from the heavier ones. And easy to imaging that this could be a problem for discovering the debris on the ocean floor. The most identifiable pieces, the engines and other heavy equipment, could have been stripped of lighter materials, thus impacted at very high terminal velocity.
This could have streamlined them for their watery descent and to partially bury themselves in silt on the ocean floor.
Of course, this is very consistent with the best satellite-based estimate of what happened in the final moments. That is, a very high rate of descent towards the ocean.