MAS was a dispirited airline in deep financial shit, which had had a bunch of serious incidents in the maintenance shops, including a fire caused by a discarded cigarette in a no smoking area that destroyed a lot of paper records.
In the weeks leading up to MH370 there were a bunch of serious safety incidents on various flights. Basically their safety was compromised for months and things finally bit them.
As for that flight - even if the flight recorders are recovered it's entirely possible the exact cause may never be discerned. Noone had anticipated an incident which could disable the crew and leave the aircraft flying for 6-8 hours afterwards, even after the Air Hellas flight showed it can happen.