The visuals are stunning, that is undeniable. I watched it in IMAX 3D HFR and the 3D effects are really awesome. You can almost forgive that you have to wear those idiotic 3D glasses for 3 hours. The story line is paper-thin, bordering to non-existent, but I can reveal that the humans return to Pandora and sooner or later Jake and Neytiri will have to face them again. While I wouldn't call the movie boring because the effects are so fantastic, it is also a fact that it is way too long.
I am a great fan of the first Avatar movie from 2009 and while it may have copied a lot of it's predictable story line, at least it told a story that was satisfying and interesting to follow. The theatrical version of the first movie was actually too short because the Extended Collector's Edition is a much better movie adding some really cool extra scenes. I have watched the first movie many times, also recently, and it is still a fine movie and the effects are still looking great. Most of all, the first movie had memorable dialogue, great one-liners and lots of humor. It also managed to make you care for the Na'vi, something the new movie mostly fails at.
"Avatar: The Way of Water" doesn't have any memorable dialogue or any humor. It could easily have had it's length cut down by an hour and it would only have improved the movie. You should never have kids in an action movie because they are annoying and do stupid things all the time. This movie have tons of smurf kids and they are super annoying and do stupid things all the time. It also has "whale" whispering. While it can be accepted in the context it also gets pretty boring after a while.
What works best are the stunning water world visuals and the action scenes. When the humans in their bad ass war machines and the mega space smurf warriors on their sea and air creatures attack each other then it's a blast. Even if the last battle drags on for what almost feels like an eternity. Again the one-liners and humor is sadly missing.
I won't get into how they managed to kind of resurrect Colonel Quaritch, but I will say that his relationship with an annoying human kid, that was left behind on Pandora when the first humans were sent back home to Earth, is beyond idiotic. It simply makes no sense in so many ways and Quaritch would never act like he does here. It breaks his character. Well, it was already broken because he doesn't say any cool one-liners any longer.
How does Sigourney Weaver fit in? Well, watch the movie and find out. It's brilliant how you can just bring back all the favorite characters that you killed off in the first movie, isn't it? Why didn't they bring back Giovanni Ribisi as Parker Selfridge too. He had some fucking hilarious dialogue in the first movie like "They're just goddamn trees!" Damn, he is missed in this new movie.
I will probably watch this movie again when it comes out on bluray because of the stunning visuals, but I sadly can't say that it is a good movie. James Cameron kind of fucked up here and forgot to add a story line, some one-liners and some humor. I hear there should be 3 more movies on the way, so maybe he'll do better next time? Time will tell.