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.
Considering the very low amount of parts found yet, they may very well belong to what the first explosion/failure has blown from the aircraft, with the main wreakage still not being discovered. Thinking of the recent Daallo incident, United 811 or the THY DC-10 near Paris in the 70s, such a scenario is also still possible.
Otherwise I do agree, if the items found so far are indeed representative for all debris, this indicates a high speed impact, which only is possible for a largely intact aircraft.