"Si vis pacem, para bellum" If you want peace, prepare for war. This quote has been around for a long time. The Latin version comes from a text written in 4th century. 1000 years earlier, Plato had similar advice.
Similarly if you want war, assume peace.
The F35 is not designed to dogfight. Form follows function. Three important forms of the F35 are
Reasonably stealthy
An impressive sensor suite
An advanced date link to share information (bidirectional) to create unprecedented battle space awareness. Note Lockheed is prime contractor for F35 and also SBIRS (space based IR system). SBIRS scans the Earths surface every 10 seconds. It was almost certainly SIBRS that tracked the missile that shot down MH17. It has been rumoured that SBIRs can track jet exhaust - certainly the US has been working on this capability for decades (Project SLOW WALKER if interested -
http://xbradtc2.com/2015/01/02/the-b...t-slow-walker/. )
Anyway, the F35 is not designed to dogfight, and it is not designed to operate alone. It is designed to operate with other assets such as missile frigates and other aircraft. So one capability (demonstrated in recent exercises) is for the F35 is to provide information to a (possibly coalition) missile frigate - both initial target selection plus en route guidance. All while remaining invisible.
Back at the time the Aust government went with the F35 (2002, 9/11, War on Terror), it seemed a safe bet that our military would always be operating with the USA. So inter-operability with US assets was seen as an advantage. This is still likely to be true, although we are living in less certain times.
There were several compromises with F35
1. Multiple versions to share development costs over a larger base of future customers
2. Single engine to keep size and cost down
There were no valid contenders.
The F22 is not for export sale.
Other US aircraft were obsolete (yes, Canada can probably get by with legacy F18 and rely on USA, but Australia is in a different situation).
Europe doesn't have anything 5th generation. 10 5th generation aircraft in development, not one of them Eurpean
China and Russia didn't seem particularly reliable sources of our future fighters
So what other choice was there?