Can a movie's sheer visual spectacle outweigh three otherwise glaring flaws: its runtime, its paint-by-numbers plot, and its sheer lack of characterization + script? I think the answer is yes, but Avatar: The Way of Water is not a movie that passes that test. It is a gorgeous movie, and follows up on its predecessors' value proposition ("yeah, the plot is hardly there, but it looks great!") with more of the same. Much more.
I think the most interesting thing you can talk about with Avatar is the tension and conversation between its plot and the film machinery itself. It is interesting and noteworthy that a movie can be so quite directly and literally anti-imperialist and anti-technological while also being a movie famous for its sheer technological prowess. It is interesting that Avatar is by all means an anti-capitalist plot that happens to be one of the top-grossing movies of all time. The most generous possible reading of Avatar is that James Cameron is trying to make this argument as loudly as possible — that Avatar is an argument for the use of technology as an act of creation rather than one of destruction.
I think that's a generous reading, but I like to err on the side of generosity.
The movie spends too much time dwelling on a lot of things that look nice and matter little. One such case that does not apply is the whale-hunting scene, a worthy use of fifteen minutes that manages to impress you with its deployment of science fiction and horrify you with its cruelty. I find myself thinking that the movie was at its best with that scene: visually stunning, emotionally haunting, and with nary a blue-skinned alien in sight.
There is a director's cut of this movie that is one hundred and five minutes and is much better. I would recommend that movie, but I would not recommend this one unless you are looking to shut your brain off for a little — and trust me, with its interminable final act, you will need to shut your brain off for a little.