I'd advocate getting each service to do what they do best, ie all vessels including landing craft should be maintained and supported by the Navy, all aircraft should be maintained and supported by the Air Force and all land based defence activities (including RAAF Air Defence Guards etc) should be done by the Army.
Thems fightin' words!
Not going to pick the scab off the RAAF-Army stoushes of old, it's been done to death.
Australia could do no better than modelling its defence force on the US Marine Corps where every member of the defence force is a soldier first, where each is committed to a common uniform, language and capability, rather than what we have now, namely; each arm speaking a separate language and not being able to integrate when the sh1t really hits the fan.
Model on the USMC? Probably wouldn't work for political reasons; won't even work on the Army alone. There has been an increasing (waxes and wanes) feel of 'AIF fetish' in Army senior leadership over the last 15 years, and a lot of trivial things imposed that attempt to water down or even eradicate regimental or corps identity. Very little saves money, and almost all of it is deeply resented, certainly outside the Corps of Boots.
Indeed I would argue that without sectional / factional / sectarian interests, and the tension and arguments that it generates, too much group-think would emerge and orthodoxies would less likely be challenged.
Combined CTs and BGs are the Army's future - it's being done successfully now. It's no stretch to see a purple future for more and more of what the ADF does - doesn't mean it has to come at the expense of identity or
genuine career choices.