The plot is clear. Just figure out that a Pandora blue inhabitant is an extra-terrestrial, then pure anagramming gives you: Na'vi ET = native. Avatar main plot is thus a basic western, just like Star Wars. Na'vis worship Nature, lives in tribes; with their bows and arrows they could impersonate fierce Indian Americans quite well, against (mostly) white exploiters.
Could it be called SciFi then? Utopia related for sure, oscillating between a green-powered tale (Heal the world...) and a Second Life warning (You walk into your dreams) with the humorous "un-obtain-ium", an difficult-to-obtain element akin to Thomas More negative places (u-topia, a-maurote). So the script is a bit more interesting than the basic plot.
Yet, although termed Cameron's long awaited child, the story is very reminiscent of both Ursula Le Guin The word for world is forest [1972/1976] (on the green side) and Poul Anderson Call me Joe  (on the wheelchair side). Or simply Pocahontas? What is left in the box is Hope.
Do You Speak Na'vi? Giving Voice To 'Avatar' Aliens:
Evoking Natives in Avatar:
Avatar' and the Culture of the Na'vi: