Verdict:

James Cameron apparently wrote a film treatment for this movie back in 1994, which makes sense because it was a couple of years after FernGully: The Last Rainforest came out, which he clearly decided to reshoot in live action, changing a few details here and there and then calling it Avatar.
In any case, utilizing the full potential of the talented cast, 3D technology and about 240M dollars, Cameron set a new bar for movies to come.
Look, let’s get the obvious out of the way: Avatar is a piece of entertainment, designed to be seen in 3D at a movie theatre or at least on a large high-quality TV at home. It is not meant to have an engaging original narrative. It’s just a very good ice cream. Just eat your ice cream.
The special effects are central to a film like this, and the graphics of Avatar are astonishing. There is hardly a frame where CGI is not present. Will all of it still look realistic a few years from now? Who knows, but it is very impressive at its release. Especially noteworthy are the facial animations, made all the more captivating thanks to all the freaky colours and lighting. Supposedly, new motion capture tech was developed for this movie, and I believe it. I feel like plopping the narrative on an alien planet is cheating a bit, because it gives the artists a card blanche to create beauty that does not exist down here at Earth, but the artists sure did take full advantage of this. Bioluminescent plants fill the screen with glowing colours and freaky animals flop and fly around.
The story is of secondary importance in this film. Neither the story nor its participants have much depth. Most of the humans are evil colonists, while the Na’vi aliens are just tall blue humans and very obviously represent a conglomeration of African, Jamaican, Native American and Arabic tribesmen, as stand-ins for all the colonized and oppressed peoples of Earth. Just as an example, the leader of the Na’vi is played by the Native American Wes Studi.
The principal plot point that symbolises both the silliness and the emptiness of the plot is the reason for humans to colonize this planet: the mineral they mine called “unobtanium”. One can’t tell if Cameron was trying to be purposefully funny or if this is the actual extent of his imagination and nuance. In any case, he’s always had a bit of misanthropist streak to him and it’s on full display in the plot.
However, the shallow plot is considerably elevated by the performances. Sam Worthington delivers a very believable fish-out-of-water performance. Zoe Saldana is very emotive as the local Na’vi princess. There is a moment when she cries out and I thought Cameron must have hurt her real family for the sake of realism or something, because her crying was chillingly realistic and soul scarring.
The trip Avatar takes you on is well worth the price of admission. It’s 2009 entertainment at its best. The experience should not be missed, no matter what your taste in movies is. However, I can see how the enjoyment would decrease dramatically for anyone who is watching this on a smaller screen, without 3D, or if they for some reason expected a deeper narrative.