I think the impediment to turning the WLM over-water lane into something like V1 is that the WLM over-water lane is much closer to the approach and over-shoot of the runway (as well as to the Salt Ash A/G gunnery range).
That's not to say it can't be done. It is to say that the over-blowing of the risks and the ease with which private citizens and all but the biggest businesses can be stuffed around in Australia makes it a tough thing to get done unless someone like Dick is threatening political ruin to someone who wants to keep their cushy seat in government.
And the requirement to file a flight plan ... well... that little tussle has been going on for decades. They'd prefer the inconvenience of manually entering details into TAAATS be out-sourced to you. The subtle shifts in language and additions of 'requirements' in AIP happen often - slowly chipping away.
