My gut tells me its not terrorism. If this was terrorism, its probably the strangest act of terrorism that's ever been perpetuated in history.
I keep coming-back to the slow-decompression theory, but that does not explain the apparent turn the jetliner made towards the Indian Ocean.
Terrorism must shock and terrorize people. People are not shocked nor terrorized, they are confused, right now.
A political message would make more sense, since people all around the world are listening to it, right now, but there is no message found yet. They attracted our attention, but failed to sent a message yet.