I really hated the story in Avatar, not because it was unoriginal (many of the best-told stories are entirely unoriginal), but partly because the "white guilt" template is not something I was ever fond of. If a movie is going to be preachy, it needs to earn it (The Empire Strikes Back is an example), and I never felt like Avatar really earned anything. Goddammit, I want to punch every single character in that movie in the face. I actually laughed during the whole burning of the hometree part, not because it was inherently funny--it shouldn't have been--but because belaboring the point for a five fucking minute sequence is just overdoing it, forced storytelling at its very worst. Show us the attack, show us the aftermath, but you don't have to dwell on every single aspect of the atrocity. It's like the filmmakers were shouting "CARE ABOUT THIS, PEOPLE!"
Ironically, District 9, which was arguably even more preachy and had a somewhat similar premise (mostly the "capitalism = evil" part), earned it. Seriously. My mind was blown by every minute of that film, until the ending, where it broke down a bit but was still strong enough not to affect the overall quality of the movie. It wasn't subtle either, and yeah, I hated the protagonist, but it pulled me in every direction it wanted to and for the most part did it skillfully and naturally. I forgot I was watching a movie. With Avatar, I was reminded every ten seconds.
But here's the worst part: everyone says it's a great-looking movie, and all I see is Lisa Frank CGI vomit. Like the Star Wars prequels, it has a repulsive visual style, so any technical wizardry falls flat. What are people seeing, exactly? The world just seems shallow, full of unrealistic and unbelievable colors. I guess to get sold on it, I'd have to believe it's natural, but I never do. The whole thing looks damn fake to me, and since it's going for realism (unlike, say, a Pixar film), that's a huge problem.
What is it about this visual style that people like?
If you want to LOOK at a movie, you're better off with, I don't know, a Stanley Kubrick film. Something remotely interesting. If you want to look at CGI, there are plenty of options for that too.