Hello Gentlemen,
No longer fly much in the region but do visit from time to time.
Mr. Veloo - with regard the level bust by the MH airplane, I guess the RT reception which is poor has something to do with it. Also worth investigating if the pilots had their headsets on or were they listening out on speakers.
For ATC - maybe an added phrase at the end/beginning of the clearance if the airwaves were not too congested - which I guess it was in this case:
"Malaysian xxx -traffic for your descent is a Cathay xxx maintaining FL380 -10nm at your 11 o'clock - descend initially FL390"
or
"Malaysian xxx - due traffic descend initially FL390"
May clue the guys in/raise their situational awareness. Hopefully the guys were looking at their TCAS display as well and keeping a good listening watch being aware of the surrounding traffic.
Always easier said from the backseat.