Am I crazy or is there a better film hiding behind the first?
Say what you will but James Cameron is a fairly accomplished scientist in his own right with his background in Marine sciences.
He writes his stories with a strong underpinning of real world physics and biology.
Take a look at the ISV Venture Star for example. It's got radiators, it travels at sub-light speed and uses a fairly plausible future design. He tends to write relatively hard sci-fi, featuring technology that might not exist yet, but there's no theoretical reason it couldn't be developed eventually.
Why is this important? Because the biology of Pandora makes perfect sense, except for one thing. The Na'vi.
The biology of the setting is very consistent. All the higher vertebrates on Pandora except the Na'vi have a 6-limb body structure.
Most higher vertebrates have a neural queue that allows the Na'vi to interface and command them, as well as to sync their minds with the sacred trees.
Furthermore, they look human... very human. They are able to vocalise in the human range and use their tools. Whilst every other organism on the planet is distinctly alien.
These are not a naturally developed species.
The Na'vi are intermediaries, created by Pandora's plant-based planetary intelligence. Based on the planet's analysis of the very first humans to land on the planet (and likely die).
The Avatar referenced in the title of the story is not the human-made avatars, but the Na'vi themselves.
The reason humans were able to make their avatars is because all of the heavy lifting was done for them already. The Na'vi were part human to begin with. Especially the neural interlink.
It's not dances with wolves in space, it's true xenofiction about humanity meeting an alien intelligence far vaster than it can understand that lacks anything that humanity can relate to. So it makes intermediaries.