An 8 year old could have written the script.
Characters are very shallow on both sides of the divide. Also it does not portray any true humanity and it does not capture any of the internal struggles that nuance decision making by people.
Its 1.5 hours of pointless action packed scenes and 1.5 hours of frolicking in the water.
Too overly ambitious and thus spends the first two hours setting up for a climax where the sky people take heavy casualties and the Navi take like 2.
It misses the point it is trying to preach. Get in tune with nature, respect life, lean on one another, learn from ancient wisdom, peace is better than war….. but if it gets even slightly hard, default back to guns, killing and solo stands…. It worked for Rambo so why not here… also put your own family above everyone else’s safety and force others to suffer and change their ways so you can prevail…
The only thing the movie has going is the animation.