The last time we had one of those was either the late 80s or early 90s, it was actually quite relevant for today as it encompassed our geography and the physical number required to simply have the required presence. Threats dictate the required capability and size of your force elements, but geography dictates the number of force elements.
When talking constabulary and HADR OPV and leased commercial vessels my do, but we still need to determine where, when, how fast etc.
In the 90s, with the post cold war "New World Order" the threat was seen to be rogue states, i.e. the occasional small boat or missile boat attack, maybe the occasional air attack, think the tanker war in the Persian Gulf, so the assumed upper threat level could be handled by an upgraded FFG or new gen FFG with NTU equivalent combat system and Standard MR, NATO Sea Sparrow and CIWS, to defend themselves and near by commercial vessels. This is where the thinking of eight or nine FFGs came from, one deployed in each of up to three areas where such attacks were likely.
The next level was the ANZACs able to provide regional presence and able to defend themselves from unexpected attack.
Below that were the corvettes protecting local waters, year round and able to protect themselves.
With the exception of the Hobarts, this is a larger and more capable force than we currently have, despite the fact the world is only a much more dangerous place than it was but also despite the fact that what is happening now has been predicted for well over a decade. Love or hate him, Rudd was telling us about China back in 2008/9, the need for small survivable combatants to replace the useless Armidales, the need for a much larger fleet of submarines, a need for a larger, more capable ANZAC replacement. It wasn't a change of government that derailed things, it was a global financial crisis and a party room coup.
The thing is we have had nothing but indecision and changing direction since, no coherent plan that we have just stuck to. In many ways that worse than building a capability that's not quite right, because at least them you would have something to build on, instead we are upgrading and life extending platforms that were ordered before the last comprehensive review.