The problem with introducing any change in the first instance is that it must be safe, and part of that process is to conduct a safety case/risk analysis on the proposed change. It may well be that the new proposed system is better and considered safer, HOWEVER, you must also conduct a safety case on the transition and in many cases the change does not go ahead because the risks during the change are unacceptable.
The other important consideration is CULTURE. It may well be that any proposed change is seen as good from most points of view, but then the change in culture must be addressed and that requires a mountain of education/training which may well be beyond the budget allocated or available???
Yes, it would be good to have a USA/FAA system in Oz, but it would need a bucket of $$'s and a significant change in the culture of the whole aviation community from the Minister, the regulator, service provider and all those that fly from ATPL to Students, RAoz and Gliders Etc Etc.
As above, a risk analysis on such a change would most likely find that the risks associated with such a change unacceptable, even tho' the end product might be highly desirable.
Bottom line.... Work on making our existing system more user friendly.
I recall a ferry flight from the UK through all those countries and the the culture of them all was that you are treated as a professional until you show that you are an idiot - cross into Oz airspace and you are treated like an idiot until you show you are a professional- that was a few years back. One can only hope it has changed. However the culture in our regulator is presently part of the problem and the new Director is yet to show that he has yet had much influence on changing it where it counts.
Now to go flying in G!!