Perhaps those who fly in the area regularly (I do not) could 'rate' the quality of the ATC authorities in the area?
As pointed out by a previous poster here, the Yangon FIR appears to me to be conspicuously worse than the others as far as comms. Singapore, Kuala Lumpur and Ho Chi Minh seem to have very good overwater communications in my experience. Singapore has the best ATC lah, those folks are great for taking you around the weather when they have you on radar. I sometimes have trouble understanding the Lumpur controllers, it may just be the accent.
However, this doesn't mean that the Burmese military side might not be awake and watching closely even though ATC will not answer.