The Vh1 version of AusNTM was heavily edited. HEAVILY. They cut 1 hour episodes into 1/2 hour episodes. The original version if MUCH better. If thats all you've seen of AusNTM, then I'd recommend watching it on the internet.
Also, Australia has less 'exotic' people than the US. The ethnic makeup is 85% Caucasian, 9% Asian (including Middle East, India, Central Asia etc.) 2% Aboriginal and the remaining 4% make up the 'rest'. And many of the minorities are heavily focused on tradition and culture, so it is alot harder to find 'exotic' girls for AusNTM.