Saw the movie this weekend. It is a technological masterpiece. That said, it is naively racists, there is simply no getting around it. It is Dances with Wolves or The Last Samurai all over again. With respect to the interviews of Cameron that I have read, his naivete (ignorance) on this point is more than palpable.
Once more, the white male is "the hero" who saves the noble savages. Even a more generous reading of the protagonist as a cipher, or as representative of humanity is problematic in that it is a reinforcement of "white male" normativity, or the universality of what is particular (white and maleness).
The movie would have been much more radical if Cameron had chosen to cast a female and/or a person of color as the lead. He could have stirred the pot a little more, by playing with gender or sexuality/sexual orientation. The aliens could have been intersex, or something along the lines of LeGuin's Left Hand of Darkness. That is when sci fi is at its best, IMO.
As kind of a cultural critic, I also am really tired of the psychological manipulation and contrivances that the media use. Of course, they use them, because they work, they are evocative on an almost organic level with human beings (true love, the myth of the hero, nobility of nature, interconnectedness, good vs evil). More creative storyline would have been nice. What about a more ambiguous hero (say like in District 9). Some of the same issues are faced, but nobility or purity are not assumed. There is moral ambiguity, and no fairy tale ending.