@Jabiru: First, thank you for your reply and your thoughts.
Maybe I was not precisly enough. Sorry for that. What I meant with "fit better" was, that the Elephant exhibit at Dubbo is located within the "Africa area" of the park, while the one (or to be exactly: the bigger one) in Sydney ist in the "Asian zone" (or surrounded with exhibits with animals from Asia).
Also - while I have visited Sydney and Dubbo - I was told from a local (motel manager), that there are only 2(!) rainy days in Dubbo (whom one of them I had the pleasure to witness it). So this would better fit African Elephant, while Asian Elephants prefer a more humid environment normally, which is basically given at a sea coast city like Sydney. But this is only an assumption/a guess and maybe you - as a person living in OZ - knows it better. (hope that was not rude. My native tonque is German, sorry).
I agree that the foliage of the exhibit is as important (if not sometimes more important) as the climatic conditions there. I must confess that I don't know the new exhibit at Dubbo (beside a few pictures). So if this exhibit is more/better covered then the one in Sydney, then indeed it is more suitable for Asians Elephants or at least as suitable as for African Elephants.
Because of the costs, my thoughts were that at least from what I know, when a zoo buys an Elephant from a official animal dealer/national park service/gouvernement, the individual price for an Asian Elephants is higher then for an African Elephant in general. But you are right. There are other costs to regard. So maybe for Australian zoos it is cheaper to get Asian Elephants. Also, my informations about this point are not really new, so maybe no longer valid.
Yeah no worries! It does get pretty hot out in Dubbo (and most of inland Australia) which probably does suit African species better, but Asian species can be housed just as well provided with funds (for water sustainability, management, etc). The Cocos quarantine station is very valuable in its proximity to Asia, so that's why many species are imported from Asia rather than Africa (I would assume not only benefiting costs but also convenience). One of the things that I am adamant in defending is that these elephants needed to be moved for the sake of their wellbeing which was compromised by the limited space in a city zoo. Another thing I am adamant about is that this is not entirely Taronga's fault; yeah they could have built a bigger exhibit but in fairness they were not expecting to house a bull at all (original plans were to AI the cows from Auckland, where the bull would be housed, not naturally bred at Taronga). I think that this is the best plan for the foreseeable future as there is just no room left anymore at Taronga (not only for the elephants but also for more exhibits.....the new tiger exhibit will have to knock down several others).