My own two cents:
Australia - I don't think it's happening. They have Red Kangaroos in the parks already, and most of the other animals (save Koala's and a few other marsupials) are too small to devote an entire land. I have read similiar explanations on this site in the past from people seemingly in the know.
The land by everest has been cleared for quite some time as far as I know. I was also under the impression that there was also some more cleared land near Camp Minnie Mickey. Wouldn't the CMM area be closer to the Animal Kingdom Lodge indicating that any construction you would hear would be coming from that area and not Asia? With that said, the construction is probably at the lodge itself for the DVC addition they plan on adding.
As for improving the park - I would like to see more animals in the walk through trails leading up to Africa (you can also access these if you take a left out of It's tought to be a bug). The last few years I've been the Capybara and Giant Galapagos Tortoise haven't been there. This would be a great location to include more animals from South America and Australia.
Rafiki's planet watch definitely needs to be improved. More animals presented in a zoo like setting would make it more appealing as that's the section of the park that's most like other zoos in the world. I was also under the impression that they had Fennec Foxes at Rafiki's Planet Watch but I have never seen them.
If they are indeed developing plots of land in Asia (especially those that are otherwise difficult to get to), then it would seem to me that the Asian Safari could possibly be in the works (this is pure speculation). However if the entrance to the attraction is easy to get to, the attraction itself can be out of the way (much like Kilimanjaro Safaris). I've long been a proponent of the expansion of animal variety in Asia with so many major animals currently omitted from the parks. There really has been little to no dialogue about Disney's progress with the Chinese government about obtaining Giant Pandas or Asian Elephants, but those two, along with Black Bears, Red Pandas, Snow Leopards and Orangutans would be an expansion that could arguably put the Animal Kingdom on par with some of the top Zoos in the country, while still maintaining the other thrills in the park that make it a full day experience.