Well, imo the A$ will only fall significantly if the RBA drops...

Well, imo the A$ will only fall significantly if the RBA drops the interest rate, while the EUR/US$-zones will increase their rates. So far the opposite is true with no end in sight. Alternatively the A$ might get hit in case commodity prices drop significantly.
Eventually major currencies (US$, EUR, GBP, A$?) will all become 1:1 and then it will become 1 global currency (IMF basket) with 'no debts'. At that time don't worry about the currency rates, just hold GOLD.