What will terrorists do with an airplane? Assuming they safely landed the plane somewhere in Asia, who are they going to attack wth it?
Even if they loaded it up with fuel and explosives, even nukes, if they planned to attack the west, they would still have to fly it half way across the world under the radar.
We are all playing a guessing game, so who knows?
IF this is a high jacking, it could be for either of two reasons.
The plane could be repainted to appear to be a trusted flag carrier and loaded with something destructive, or there was someone on board that the Malaysian government wanted to dispose of without causing an international incident.
So the plane disappears.
Or kidnapping for ransom.
The behaviour of the Malaysian government causes me to lean more toward political intrigue.
I think it is obvious if you give it some thought.