MrDK:
If the recorders of MH370 are found and it proves that only the last two hours of (possible) silence is available, when the first two hours of flight may be the most critical, then I hope the industry and regulatory agencies will recognize that improvements are in order.
If that turns out to be the case, 2+ hours of silence would at least clarify that whatever happened on this a/c all took place near to the point of deviation from the FPL RTE.
The investigators will still have forensic science to answer a lot of other questions with enough accuracy to at least rule out or confirm whether the little green men were on board the aircraft the whole time.
