Lawrence of Arabia is also a flik that had a "man goes to another culture and adopts their ways" sort of thing that turned into a total war picture, and its typically considered one of the best movies of all time.
Of course, no one is pulling up THAT reference, because that movie is, you know… 40 years old.
Or hey, Princess Mononoke has a guy leaving his home and meeting up with a bunch of natives and hanging out with beasts, and falling in love ith a wild girl, in a jungle even, and its not even remotely the same movie as Dances with Wolves.
Avatar isn't out yet, no one but the people that worked on it knows exactly what its going to be, just what a couple minutes of previews give away.
The 3 hour run time make me hopeful, rather than scared. And Cameron's track record of Terminator, T2, True Lies, Abyss, Alien, Aliens, Titanic, etc. means he gets the credibility and benefit of the doubt.
Seriously, if you're going to insult a movie that no one has yet seen, based on 30 seconds of promotional material because you absolutley MUST scorn it, don't compare it to the 1990 academy award winner for best picture, and don't just rehash the easy South Park joke. Pick something stupid and insipid that has the same theme.