Apart from being annoying as sci-fi, a more serious flaw is the deification of the Great White Man. What, you say? It's a celebration of native, tribal, nature worshipers. Yes it is. But they need Jake Sculley, the White Man, to come in and save them, which he does by assuming the most sacred role that we know any individual Navi has held. And I didn't get any feeling he did this by great spiritual enlightenment, but rather by a logical calculation that this was what he would need to do to be able to lead his new people to victory. Yuck.
I don't say this all the time. I'd heard (white) people saying this about Dances With Wolves, and I didn't buy the argument. He doesn't save the Lakota, or even his village. And, in what I found a particularly compelling angle, the Lakota did not view the Americans as their Great Enemy. They had older issues with the Pawnee, and the Americans were simply a bizarre force, that people were only starting to realize was as a threat. I'm a white man, admittedly, but this carried authenticity to me.
Jake Sculley did not need to become a demigod to tell this story. He could have simply brought critical, decisive insights about the humans, given it to the Navi leaders, and joined them as one of their warriors. Little would have to change. In some ways, the giving of critical intelligence might have underscored the betrayal more than the assumption of a leadership role in the opposition. Because such a betrayal can be done with humility, it can be done to empower the Navi to defend themselves. It carries with it the possibility that Jake would unleash a power and destruction he could not control. A better, more dramatic, more plausible, and less offensive story.