First blog. Bear with me.
I saw Avatar 17 times from the time I saw it in theaters to June 2010. I noticed Parker, before the attack on Hometree, and the final battle, is upset with it. In the "You're a long way from Earth" deleted scene, he goes all out on Quaritch, trying to stop the battle. In the deleted "Drums of War", he covers his face in his hands, when Quaritch says he'll drive them out with gas.
So, Parker is one of the heroes of the film. Antihero, but hero. Dispite wanting the money, he still cares for the Na'vi.
If Giovanni Risibi returns for Avatar 2, he might be a hero, and not a villain.