1. Malaysian politics is turbulent and corrupt, but generally not violent.
2. The trustworthiness of Malaysia's current government is not beyond doubt in light of what has emerged in connection with MH370. (See, for example,
this interesting discovery by D.S.)
Given that the captain was reported to be a vocal supporter of Malaysian opposition leader Anwar Ibrahim, "official" statements concerning the (now absent) captain should be treated with great caution and checked closely for factual backup.
Anwar Ibrahim would decidedly not wish to be associated with any criminal actions by a prominent supporter.
3. There have been many comments about the high level of flying skills exhibited by the hijackers after MH370 lost contact with ATC.
However, going through the best scenarios available at present, hard
flying skills involved are minimal. The aircraft went through a few turns and changes of altitude. Indeed, some comments here appear to indicate that the only "flying" that occurred may have been achieved through step-by-step programming of the FMS.
Where the hijackers have exhibited great sophistication is in their ability to evade ATC and various radar systems based on a shrewd understanding of the
practical limitations of those systems, likely acquired through extensive observation. However, such knowledge and expertise is by no means confined to professional pilots.
P.S.: There may be only a single hijacker.