You listed more sports stars than real achievers. That makes me ashamed to be Australian. It is typical of Australia to think that being good at sport is something really important and noteworthy, whilst science, education and art are all elitist pursuits and viewed with a sort of mild disdain (although I acknowledge you listed a few such achievers). Being able to run very fast does not make you a good person. Winning the cricket does not make you a good person. Don Bradman was a great batsman, but he still allowed religious differences to come between him and his team mates.
As for the 'minor' issues that you so casually brush aside, Australia is facing a great moral challenge and many Australians are unwilling to even admit that it exists, let alone resolve it. The 2001 Tampa Crisis and various subsequent refugee-related controversies have been a horrible exercise in manipulation and xenophobia and have helped to bring politics in this country to new depths.
I strongly believe that an Australian (or anyone) who lives in an ostensibly free society has a duty to care about the actions of the nation as a whole. Although I would never suggest that there are parallels between Australia and wartime Germany, would you say that the apathy of ordinary Germans made the holocaust ok? To show you that I'm not just ranting, here's some words from wiser heads than mine:
"The darkest places in hell are reserved for those who maintain their neutrality in times of moral crisis." - Dante
"The only thing necessary for the triumph of evil is that good men do nothing." - Edmund Burke
"Now that no one buys our votes, the public has long since cast off its cares; the people that once bestowed commands, consulships, legions, and all else, now meddles no more and longs eagerly for just two things--bread and circuses." - Juvenal
So, rather than glibly suggesting that those who don't like the way things are going in Australia are free to leave, perhaps some Aussies should turn off the sport and take an interest in what is happening in their own country, or maybe leave themselves.