I do think Dick has a strong point here, and Airservices do provide a substandard ATC service compared to the US. Some controllers seem to get flustered anytime there is more than a couple of non RPT aircraft in their sector. Only have to look at how restrictive they have been with ILS training in the Melbourne basin over the years. They forget when denying clearances in the modern age we can now see all the same traffic (or more likely lack of) ADS-B returns on our iPads as they see when assessing the traffic load and deciding whether to fit a GA aircraft into the flow or not.
Without doubt the back and forth between the class D & C controllers and the ultimate refusal of the clearance was a contributing factor to the accident (especially with no IFR arrivals or departures at Coffs Harbour at the time). However the pilot only needed to get a forecast including a sat pic and plan his flight coastal seeking a not above clearance/transit through Coffs’ class D to have ensured a totally different outcome. Perhaps filing a flight plan may have also helped with more efficient handling by ATC as well. Very “relaxed” attitude to airmanship by the PIC to put it mildly.