It is very simple logic. When world is awash in cheap money, even slightest yield advantage will attract billions. So in a nutshell, RBA and RBNZ are in futile fight. They can just hope that world would be a better place where they can survive higher rates because no matter what these countries will offer higher rates then US and EU, either in doom or gloom. Right now investment outlook is soggy and that's why rates are around 1.50 but when things will be better it will be 4 or 5, which US and EU will never able to achieve. Thus, AUD/USD will always be ready to run higher.
Of course it is too early to jump on but we will be looking for opportunities to get long AUD/USD from better levels. Also AUD/USD is facing some technical hurdles which will prevent it from racing higher. When fast money traders who are long from wrong levels are shaken out and AUD/USD falls to 0.7200 / 0.7000 then it will be really juicy to grab. Along with RBA we are also praying for the same thing - AUD/USD below 0.7000 ;) So that we can grab a boat load of the stuff. We are not looking for 20 / 50 pips here but at very low levels it is going to be a month or months long trade giving at least few hundred pips. It has given in the past and will do it in future too :)
Wise words for central banks are that instead of searching panacea by just lowering the rates and getting competitive advantage, try to use some common sense and pass the baton to politicians for better reforms. Because if RBA wants AUD/USD at 0.6000 then it won't be there by rate cuts but it will nose dive to that level when their exports are plummeting again and world is again in very dire situation like GFC. So RBA, be careful for what you really wish for ! If you really want riots on the street by jobless and people beating Bank CEOs on road for not giving anything to virtuous savers then you are on the right path ;) ( And actually that applies to US and EU too ) Rather pray for global growth and rate hiking cycle, because that's the way for long term prosperity.