All I will say about Avatar is that I couldn't help but thinking that I was watching our generation's "Wizard of Oz", which I really think it was.
I think it was pretty clear that this wasn't going to be a deep movie. The general message of it was that big corporations and national interests are evil and disregard more important human concerns, like culture. I'm fond of that message frankly, and it's exactly analogous to the colonization of the Americas and "white man's" absolute disregard and dismissal of the existing cultures; cultures that we could have learned a lot from.
So, if some 6 year old kid can take that message away from Avatar, even subconsciously, that's awesome. I'm not that offended or surprised by its lack of 'artistic merit'.
That being said, it's not on my top 25 list of movies, but I enjoyed seeing it in the theatre for the first time.