I saw this in the theater and came away feeling the same way. Back when the first movie came out the CGI was like nothing we'd seen before, so he could have got away with a mediocre plot if he wanted - but the plot was actually pretty decent too.

The Way of Water just felt like the first movie all over again, just in the ocean. The same humans want to invade the same planet and fight the same aliens with the same weapons. The same bad guy fights the same good guy. It's a rehash with very little originality to differentiate it from the first.