As a pommie, I've found this pretty interesting reading
One observation in particular that strikes me is that some folk feel that there's an Australian identity that is struggling to step out from behind the 'colonial' flag.
But here's the thing...there is no empire. The colonial days are long gone. Many countries are allies, as Australia/NZ are with the UK and USA.
If you ask people on the street in the UK about Australia, what comes to mind is this awesome sun-drenched land, full of spirit and adventure. There's no sense colonialism. We speak (more or less!) the same language and there's some not insignificant common heritage, and generally a sense of friendliness.
All the Australians I ever met before moving here were all larger than life, proud Australians full of the spirit of Australia. Believe me, the Australian identity as perceived from abroad is not a slave to any flag!
It's not for me to say either way, but I could probably come up with some pretty interesting suggestions

in particular, I like the crest of the Australian government, but I'm sure that'd go down like a lead balloon