Seriously. Out of all the characters, he was actually the most terribly written and one of the worst written of any Cameron film (and that's saying something). The problem the movie has isn't "simplicity" (Simple movies can be great. Most recently, I liked Princess and the Frog.), it's that there is no nuance: it's all really swinging a big club around and hitting the audience over its head, as if people are retards.
And the illustration of this point is his character. In each successive re-watch, he becomes more and more a representation of the movies glaring flaws. He is comical to watch, completely unbelievable as a human or anything. He is less human than the Na'vi. His only purpose is to be the embodiment of the ALL GUNS-NO-TALK foil to the Na'vi way of life, and as a result Cameron breathed absolutely no life into him. He might as well be a wind up doll, screeching out prepared catchphrases to the glee of little fucking children.
I have issues with the rest of the movie, but this character is the one part I would genuinely hope the movie gets a Razzie for. He is so fucking abysmally written that it's borderline offensive.