I watched Avatar on Saturday afternoon, and I can confirm that it suffers from all the weaknesses that its detractors point to. The plot is a crude rendition of Dances With Wolves made by a guy who clearly spent his teenage years getting high and listening to Yes. The characters are paper-thin, the dialogue is not awe-inspiring, and the whole amounts to a half-baked fantasy stemming from white guilt.
If any of those criticisms were relevant, I would agree that Avatar, for all its technological accomplishment, is a lousy film. But the plot is just a rough bridge laid down for the world of Pandora to cross from Cameron's imagination to the screen. Once the bridge has been crossed, how cares how sturdy it is? No one's using it again.
The plot of Avatar is nearly as old as dirt – or more precisely, it's as old the first time one tribe decided to take another tribe's dirt. Paraplegic ex-Marine Jake Sully ships off to Pandora, a far-off moon where a well-financed corporation (Weyland-Yutani, maybe?) is attempting to negotiate with a group of indigenous aliens (the Na'vi) to gain access to a whopping deposit of precious minerals. Jake arrives at the point when years of diplomacy and cross-cultural relations are breaking down, and the use of force is rapidly becoming the preferred option.
Although Jake is a grunt, a piece of happenstance selects him for the Avatar program, in which he gets to occupy the body of a vat-grown alien and interact with the locals in a form that they will accept (a 10 foot tall Thundercat, apparently). Once in the avatar body, Jake gets into trouble and is saved by the daughter of the local clan leaders. Jake is tentatively accepted into the tribe, falls in love, and turns against the invaders. Even better, he gets to lead the Na'vi in battle and send the chastened humans back home.
So much for plot. Avatar finds James Cameron exploring the same obsessions as always: entombment, displacement and the search for home. In Avatar the hero is entombed and displaced into another body. In the Terminator films, the heroes are sent backwards in time. In Aliens, the heroine emerges from sleep to find that nearly sixty years has passed. In all cases, the characters are outcast and lost, and their story is a quest for home. Cameron appears to be showing us Dances With Wolves, but underneath all that fancy dressing, he's offering us another version of The Odyssey. Once looked in that light, the movie turns on its axis and offers up something wholly different and a great deal more satisfying, in part because Cameron's homes are never where you expect them to be.
But why call the movie Avatar? It seems like a pretty flabby title. In the context of the film, an avatar is a substitute body, and that doesn't seem like a promising name for a blockbuster. The film is full of substitutions and prosthetics - the Space Marines walk around in gigantic mech suits, descendents of the loader exoskeletons from Aliens; Jake gets around on a wheelchair; and every interaction with the environment of Pandora must be done behind a mask or a wall, since the environment is toxic.
The ultimate prosthesis in the film is the big blue avatar (I'm glad they didn't call the film Prosthesis) that Jake uses. The Na'vi find the avatars repulsive, calling them 'false bodies'. But how can a body be false? What they mean is that the body does not properly belong to the mind that occasionally inhabits it. When not filled up by the consciousness of the human, the body is limp and unresponsive, utterly comatose, a corpse that will not die. Like vampires and zombies, the avatar exists in an unresolved state, and the story of the movie is about the resolution of the avatar. Will Jake keep his body, move exclusively to the new one, or continue to live in both bodies at once, never truly sleeping or waking?
The problem with inhabiting the avatar, as Jake begins to realize, is that you begin to relinquish your claim on your original body (In a nice twist, Jake himself is a substitute for his dead twin brother, so he is already a kind of avatar). He confesses at one point, his hair unwashed and his stubble verging on beardhood, that he longer knows who he is.
What he means, entirely aside from the ideological and cultural divide that he constantly crosses, is that he has begun to understand his own body as an avatar as well. Once he begins to occupy two bodies, one a gift of biology and the other of technology, then the real story becomes clear: how will he resolve his divided self? How will he behead the zombie or stake the vampire? How do you solve a problem like Jake Sully?
The great battle at the end of the film, in which alien-Jake leads the Na'vi clans into battle against a well-armed military (themselves in mecha suits that are a type of avatar), is a version of Odysseus killing Penelope's suitors. In this case, Pandora is the bride, and the humanity his rival. The twist that makes Avatar enjoyable is that Sully arrives on Pandora as a suitor, unaware that he is really the long-lost husband. Watching him reclaim something that was not his in the first place is the movie's chief pleasure. That and watching people get hit with five-foot long arrows.