My comments here are predicated on the aim being INDEPENDENT continental and close regional defence.....not silly adventurism with the United States.
I think a fleet of small, tough, adaptable and nimble workhorse jets would be invaluable as a defence asset.
These could be designed and built here, using capital subscribed by, in the majority, Australians, to a long term supply and support contract with the Federal Government. If manned, the pilots could, potentially, be part timers.
If the project delivered a useful capability for the money spent, consideration could then be given to having a go at a big fast, long legged and high flying weapon hauler. There are lots of aircraft to copy..,er, draw inspiration from. F-111, TSR2, SU-34 and 35 and T-50, Avro Arrow.
It is beyond me why we continue to stir the Russians. Maybe they would be pleased to offer a deal on some truly superior aircraft, with possible local production.
Australia is defendable. It does take organisation and forethought.