Seems like when I hear Tasmanian Christians get grumpy about Avatar, it's cause it's too blockbuster, and cliched and simply CG eye-candy.
Seems like all the noise I've heard on the net from American Christians getting grumpy about Avatar (like Driscoll and Southern Baptist Seminary) it's more because it's about nature worship and anti-capitalism.
So there's some truth to both. Although I reckon the Tassie Christians are being a little snobby and the American Christians are being a lot reactionary (I'm aware of the fact that comparing a State of 500 000 and a country of 300 million is ridiculous, btw).
I reckon you'd have to be a bit silly to think anyone will be moved and influenced deeply by Avatar's anti-capitalist message and even sillier to think Avatar is a powerful advertisement for animism. In reality, these things are merely the background presuppositions that give the film some thin semblance of a narrative. It's not really about either thing, as far as I'm concerned.
In my mind, the film is a documentary. And a beautiful portrayal of a wonderful, fantastic world. As a celebration of human imagination and a display of our deep longing for paradise, it's a huge success. As a vehicle for animistic or primitivist ideology its ordinary and definitely not something for Christians to get too worried about.