My bet is that the plane experienced a sudden decompression, the pilot tried to turn around to get back to Kuala Lumpur, but the pilots both blacked out because they failed to put on face masks in time. The debris is far out in the South China Sea somewhere.
That's my bet also. Except the pilots were turning the plane back after the decompression event (they should have donned the oxygen mask as first priority) so the plane could be in the Indian Ocean.
