As far as comments about Roeg's going overboard with his message of "nature/aborigine good, industrialisation/white men bad," this is a simplistic way of reading it. First of all, every director has his or her own style, and Roeg started as a cinematographer--his movies tend to contain long, meditative (or, boring, depending on one's view) visual passages. Roeg floods the screen with cascades of images, by turns repetitive and contrasting, much as a poet uses the sounds and rhythms of words, as well as their semantic content, to create "meaning" in the context of the poem.
To expect Roeg not to dwell on images is to expect Tolstoy not to go off on 20-page rants about how the lack of Napoleon would necessitate another to fill his historical role. One overlooks idiosyncracies in one's friends.
I found the movie much more powerful than I expected. My only disappointment with the Criterion DVD release is with the commentaries. I would love to have heard more about the story, and it would have been nice to have heard from David Gulpilil, whose role as the aborigine was a watershed in Australian cinema, as noted in the IMDb article on his career.