I'm not too worried. I think it's important to remember there is still a lot to come and I am quietly confident we will see some Aussie animals sooner or later. Some foliage would be great too, like some eucalypts.
Personally I'd love to see a tree kangaroo, cassowary, emu, black swan, cape barren goose, common wombat, some wallaby species and Tasmanian devil... as well as the obvious kangaroo and koala.
I haven't played the beta as I am about to go away and will wait for the launch in November but one thing I think I saw in game is a metal fence which looks a lot like colorbond steel fencing, something which will be very useful for building authentic looking Australian zoos.