Indeed. ETOPS/EDTO etc is a planning exercise. More often than not, you have other suitable and adequate fields you can utilise. It doesn't require you to land at the nominated ports, you're just using them to comply with the rules.
In an emergency situation, you can do whatever you believe is the safest option. Provided of course you can justify your actions and decision making.
Air Asia, CTAF, NPA and limited support? It's a no brainer they went to Perth.
Ultimately our job is to land the aircraft in one piece with everyone safe. How you get it there is of course always up to much debate. The job was done and the crew should be commended for doing their best and delivering 350 souls home.
Well done guys.