I always find it interesting when someone on the ground sitting behind a screen (or not) cops some blame for an aircraft accident. In this case the pilot was clearly the one make ALL the decisions except for the one that allowed him through Willy.
Willy non clearance in this case was a small contributor but not the cause. Any pilots flying in and around Sydney for any more than five minutes know Willy is unpredictable with clearances and the reality is if your planning this area you need a back up plan. Its common sense. I cant see in all seriousness how we can blame Willy (no I am not military).
To draw a comparison - A friend of mine crashed in a Cheyenne at Benalla back in 2004 and the controllers were found partly to blame there because they knew he was well off course for some time and they didnt say a word to the pilot even though he began an RNAV in bad weather. In that case I agreed with that finding.
When you stack the odds against yourself like this guy in MDX did it only needs a couple of things to go wrong and your in serious trouble very quickly. Plenty of other outcomes were possible had the pilot taken better decisions - and we are all not immune to this.
But yes Dick, in this day and age we should have better ability to plan and fly through Willy - especially since we are all having to invest in ADSB and a very high level of fault tolerant GPS units. Surely we can use this technology to provide a safe lane (either IFR or VFR) through.