Anyways the biggest problem right now is this. The the F-22 is the absolute best in the world but expensive and now apparently even more expensive to maintain.
It's best, if it flies, does not suffer a catastrophic error, USAF can maintain them, does not cross international dateline and could be present at sufficient numbers to actually make a difference. It's super hyper awesome if it happens to be fighting an enemy which has those airplanes that do not exist yet - otherwise it's redundant (many other airframes give the same performance) or useless (a grounded airplane is useless).
edit: Without AWACS, the stealth is kinda useless as well, since in order to see anything without AWACS support - remember that this thing is made to combat superpowerful nations that do not exist yet, so AWACS is not given - F-22 has to turn its radar on, and blamm, it's quite visible. And other nations also possess, and are actually quite far ahead of USA, in developing anti-stealth radars. And in case radar is completely off F-22's size and not too good fuel capacity or manuverability in combat don't work in its favour.
Without defective stealth and more emphasis on air-to-air F-22 would be a great plane. Now it's just... an expensive one.
The F-15 has an amazing record but the latest Su-27 variants (Su-30MKI and MKK for instance) that are available for export are better in most respects. The F-16 is still a great aircraft and many of them are relatively new but they can't do everything. The F-18E/F is a great plane but its not good enough to win outnumbered by the latest Su-27 models. Plus all of the older models despite being quite good are ageing and there are cracks in the airframes forming and all sorts of bad things.
You hit the nail on the head on the last paragraph. Currently, the performance of current models of Russian or Chinese fighters is not a threat to US: the training, force multipliers, numbers, electronics and all the other stuff presumably give huge advantage to US airforces, though that is of course quite speculative. However, the updates and maintenance can only keep fighter aircraft flying for so long; finally we meet a situation as with F-15s that the airframes simply break.
The complete farce of fighter developement of 1980s-2000s in West - and in Russia as well - has left many nations with dimishing choices: either the small multirole canards like Gripen, Typhoon or Rafale, older planes with limited flying time, Russ--- scratch that if you're a NATO country or something close to that - or complete reliance that the US et al can actually get the JSF program working. You can only recycle old frames for so long. And now you see what US gets for scrapping all other programs: absolutely nothing at all.
So take Australia which faces the real possibility that everyone else in the region is going to have something close to the latest Su-27 export model which is largely better than the F-15 and you are relying on ageing F-18C models for defense...things get interesting for the purchasing experience. The F-35 is capable but its not massively superior and isn't proven. The F-22 is not for export and has problems.
It seems like the winner of the current generation of aircraft is an upgraded Su-27 or the Typhoon which seems to be well liked and doing relatively well in exports. Its rarely a pure performance game...
It's always a politics game. Airframe is only one thing; it needs radars, communications, computers, spare parts, weaponry, training, numbers and someone to pay the bill to become a fully functional death machine. I would bet Australia to follow the general Western suit and go for F-35 or perhaps Typhoon.