[Iluvbertie]

Had they done this 100 years ago they would have had to make arrangements for succession separate from the British.
Afterall the Norwegian royal family are in line to the British throne through a daughter of Edward VII.

My idea would have seen, say Arthur Duke of Connaught become King of Australia and his descendents would now be the monarch here without necessarily losing their rights in Britian but the understanding would be that if they became the monarch of Britain they wouldn't remain as monarch here. By now they would have established themselves in Australian psyche and be seen as Australian rather than foreigners because they would have been living here, raising their kids here, representing us alone etc.

As they didn't do that we are growing away from Britain, in my opinion.

Had this scenario happened I expect the 3rd Duke of Connaught would have married or alternative arrangements made to pass the line to his aunts line, including the younger line of Sweden (assuming the same marriages had taken place).

Queen Victoria has a couple of thousand descendents so it would have been possible to set up lines of succession to cover the different realms but now it is too late, in my opinion, and eventually Australia will cease to be a monarchy at some time in the future.