Since the pilot asked for a change in flightpath can it be assumed that the pilot didn't realize the danger the TS posed?
I agree with the fact that the PIC has the right to make decisions in order to save the aircraft but the PM needs to notify the atc before the decision is carried out or in adequate time. Otherwise their could be risk to other nearby planes.
"XXX Center, Air America 123 is turning to heading 270 and climbing to FL 380 for weather avoidance due to urgent conditions" is a far different statement than "Air America 123 requests a left turn to 270 and a climb to FL 380 for weather avoidance."
What I'm trying to get at here is the need to be assertive with authority (in this case ATC) when there is a possible danger to the aircraft. We will get the answer soon enough as to whether the Air Asia flight knew that there was a danger due to weather or whether they flew into it by accident; the latter case being well within the scope of possibility. In the meantime, what I'm suggesting here is the need to use one's authority as PIC to do what is necessary to keep the flight safe. With ATC informed and TCAS, the risk of a mid-air is low.
What I don't know is whether deference to authority is part of the culture in this part of the world and whether it may have played a part in how events unfolded. Here in the US, I view ATC as an asset, albeit one that I can override if need be, which is admittedly a very rare circumstance. Pilots in other parts of the world may have a different view of ATC.
Noting your location, you probably have more insight into this than I do but your initial response seems to indicate a different view of how to handle an urgent situation by suggesting that a request indicates a recognition of urgency.
I'm open to correction if I'm wrong in my assumptions here; I'm here to learn rather than pontificate.