I'll just put my 2 cents in in regards to the ADF and the A-10. While I personally believe the A-10 to be under valued in CAS (Statistically it is the safest CAS platform behind the AC-130) by members of the forum I don't see it being a viable option for the ADF ever.
The RAAF is only so large (same goes for the ADF as a whole) so there are only so many aircraft we can operate. Acquiring the A-10 would mean giving up or reducing the number of aircraft else where? Less P-8's? E-7's? C-17's? C-130's? KC-30A's?.....
whose role could be filled by attack helicopters flown by the Army.
You ask the question and supply the answer.
Want a dedicated CAS aircraft to support Army?
But what aircraft would be sacrificed to allow their operation?
The Tiger Attack helicopters.
Don't even need a "high end" aircraft like A10 to offer a better CAS capability than a Tiger. Something simple like an Iomax Archangel (crop duster modified aircraft) offers vastly more CAS capability than any attack helicopter.
More Survivable: Can operate above 20,000 feet out of MANPAD range or 50 feet above the ground.
More Endurance: 10+ Hours
More Range: 2,500 Km.
More Payload: 3000Kg. 7 Weapons stations.
More weapon options: Can carry Hellfire, 70mm rockets, gun pods, Laser Guided Bombs( up to 12 LGBs!) or a combination of all.
Costs less to buy.
Hourly cost of operation as little as US $1000 (v AUS $30,000 for Tiger)!
That statistic alone is mind blowing. For similar hourly costs you could operate 1 Tiger or a whole Squadron of 16 Archangels. And not only that, EACH Archangel could be on station for 3 times as long as the Tiger.
No brainer really.
Oh wait.
Army doesn't control fixed wing aircraft so they won't want it!