Thanks for the rules there Christep, seems as though they've tightened up the fare unfortunately, makes it a little less appealing. As for the pricings in Australia, I managed to follow up on it over here and the rates I got quoted for the various ranges were:

22Y: $2949
26Y: $3599
29Y: $4229
(agreed, certainly better value than Hong Kong)

So it's definitely looking like if I'm doing the South American option that the 5 continent OneWorld Explorer wins out, even if I end up squandering the European leg of it - it's only $3159 and a whole lot more flexible for routing. Thanks once again for all the assistance!