Yea....but flying lizards!
Heh. And in fairness to Cameron, apparently it was unnecessary to provide motivation for Jake wanting to live on Pandora. The entire audience wanted to go to there too because it looked pretty.
The entire movie lacked motivation for any characters. It was basically a really pretty movie with a good amount of unmotivated action. Had the movie spent more time explaining WHY the characters were they were and had us sympathize with even the worst of them, instead of just showing us as many plants and animals as possible, it would have been a lot better.
Hell, maybe this would have worked better split into two movies, one being about the motivaton, the other being about the fight.