Yes: The 'who' and the 'where they sit' has substantial importance, but I would suggest that the biggest issue is that there are no precise, objective risk/cost criteria by reference to which classes and volumes of airspace are determined in Australia - at least not that I can find publicly. And I don't count 'ALARP' as it is not sufficiently precise.
I am talking about actual probabilities of collisions and actual costs put on the lives lost and risk mitigation actions. Someone like alph centauri can articulate these criteria better than I can.