It is an important element, no doubt. But movies very rarely have such overwhelming success based on just that element. Just as an example, Blade Runner 2049 is a visually STUNNING movie, and that movie came and went at the box office like a fart in the wind. And we can hardly pretend that Avatar wins many points outside of it's visual presentation.
Well, the movie isn't bad. It's the type of movie that works for the big screen more than anything else. Its super high quality which is what a lot of big budget blockbuster type movies try to appeal to that audience. If you liked the first movie you probably will like the second. Probably one of the best movie that uses water I have seen. As to the plot, well it can be hit or miss depending on what you are looking for, either way it was a nice experiece for myself and my family.