The ADF is too small to break it up any more. The US can do it, because, frankly the USMC is proberly the 2nd biggest Navy and right up there in terms of most capable army. The RNM have a long tradition, is still sizeable by itself and they can afford to specialise.
ADF can't. Our 2 LHD when used together as planned will deploy over 2,000 troops and equipment to sustain that, we need our whole Army marine capable or atleast familiar with it. And if the poo hits the fan (as it did in WWII) they will have to get used to marine deployments anyway. We won't be so lucky as to be able to deploy off a painted ferry.
Whats the term GF uses? Purple?. RAAF, RAN and RAA all working together. I think thats going to be one of the strengths of the ADF is that because we are smaller, we will have to work harder together to achieve what we need. While we don't need to abolish names like Canada did, we should see ourselves as a completely intergrated force with out specific geographic territories as each branch brings something to the table for each location.
RAA should become very familiar with the LHD, as its going to be a pretty much every major deployment of the RAA.