First off a comment on Carlo Kopp. I would agree that he had an incredible bias for the F-111, it was pretty clear he thought that was the one and only solution to Australia's problems. Putting all that aside, his other articles about China, Hardened Aircraft Shelters, Indonesia and others were quite interesting. It was many years ago he pointed out (I'm sure others have too) the inadequacies in RAAF logistics planning, lo and behold the last White Paper finally pointed out all the holes in the logistics chain for the ADF!
The ADF and Government have been masters at equipping our military 'for but not with'. By that I mean they might have a ANZAC Frigate but it hasn't been regularly upgraded with new sensors or anti missile defences to enable them to participate in high intensity conflict. Whoever is driving the more recent acquisitions is taking the ADF in the right direction. If there's one good thing that's come out of East Timor, Iraq and Afghanistan, it's that the Government finally realised they need to properly equip the ADF!!
The F-111 was a great aircraft for Australia, I would almost say it was perfect. Even in 2008 it was a formidable adversary for the F/A-18's to chase down. I spoke to a fighter pilot in Katherine and asked him specifically about it. He said if the F-111 guys figured out they were being targeted before the F/A-18's got close, they just lit up the afterburners and outran them. But like all good things, they must come to an end. There is no direct replacement for the F-111 so we must pick from what is available.
Basically Australia only had the choice of American equipment. First off anything European has political implications given we are generally at war as partners of the USA. Plus something like the Eurofighter doesn't have a clear upgrade path. The different partners are developing their own modifications, which would mean Australia would have to do the same thing instead of being able to buy it off the shelf for US equipment. The F-15 is old, yes they still build them new, yes they are still capable, but we are talking about a 40 year old design. An aircraft that various hostile powers (China, Russia, etc) have developed weapons and tactics to defeat. In the next 20 years the weapons capable of taking down an F-15 is only going to increase and leave that aircraft vulnerable.
The F-22 is not for sale. So that leaves the F-35. Should we be buying a fighter with two engines? Yes! (The RAAF had the same requirement as Canada when they bought the F/A-18) But we can't, so lets move on from that issue. The F-35 has stealth, from the front mainly. There's the first advantage over anything except the F-22. If the other guy can't see you how can they attack you? Is it as good in a dogfight as an F-15 or Su-30? Probably not but if the F-35 gets the first shot (because of the stealth and networked information), there's more chance they'll win. The networking features are the game changer here. The Super Hornet is partway there but the F-35 has it built in from the start. Why is this important? Look at the 1982 Israeli campaign against Syria. They used the first example of networked information to achieve air superiority. Again if the F-35 receives information without having to turn on radars etc they can engage the enemy when THEY decide. In war information is always the key.
"Know the other, know yourself. And the victory will not be at risk. Know the ground, know the natural conditions. And the victory can be total." - Sun Tzu
Australia also needs a strike capability. When the F-15 was first designed it didn't have this ability, much like the F-22 today. The F-35 has this ability. We need the capability of striking maritime targets off our coast.
As for the argument of whether we should even spend the money on a defence force to begin with, I'll leave you with this thought. The German Luftwaffe went from zero to beginning WW2 in 6 years, plus some prior illegal training in the early 30's. So if it takes a focused dictatorship 6+ years to create a credible Air Force capable of waging war, how long do you think it would take a dithering democracy? 10 years? 15 years? Do you think any Australian Government is capable of seeing a credible threat that far out? I don't think so...
There's a story of an RAAF Officer that was given the mission to determine how best to defend Australia in the 1920's. In summary his answer was the threat will come from the north, most likely through Darwin and we need XX number of squadrons to defend the country. He was effectively laughed out of the room and denied any further promotions for such 'preposterous' rubbish!! I think he was in Darwin when the bombs fell in 1942... (I'm sure I've read a book about this guy, anyone know it?)
"Only the dead have seen the end of war" - Plato