I'm sad this ugly movie turned a profit, particularly for what a great film it could've been.
Character progression for both Jake & Neyteri moves backwards in a disengaging and unbelievable way, which is particularly noticable after rewatching the the first film. The new characters are objectively flat (one dimensional), and irksome (one character's *every* line to a handful of other characters very inorganically begins with 'bro').
Wide swaths of dialogue feel truly unnecessary; words said for words' sake, with no added value. The sloppy Deus ex machina revival of the original villain (forgivable, if they otherwise made a good film; even with a bad origin in this movie, he's still the best character).
The oh so poorly choreographed handling of the human 'prisoner' throughout the movie (oh he's running away? Pretend like you're trying to catch him. He's bashing people & equipment with a fire extinguisher while folks are dieing outside? Gently tell him to stop. No luck? Just calmly, without visible exertion, pull him away).
Spider's entire character shows itself to be an obvious farce throughout this movie.
The poorly handled power dynamic/sharing of knowledge from the children to their parents at the end. It's a laudable objective, but it was not done properly (the movie makes a point to set up the distinction early on, but, other than the first movie's protagonist inexplicably having less will, drive, passion, & intellect in the second movie than he did in the first, there is a significant lack of plausibility here).
The world building of the water clans (where this movie 'shines') was still less engaging than the same exploration of the forest people in the first movie.
Overall, the interesting elements, spread paper thin throughout the lengthy film, are far overshadowed by all of the negative aspects. It was too long for all the poorly written dialogue, lack of character progression, & middle school plot points. It feels like they wanted to make a good 6 hour movie, but they so badly bungled the cutting of it into 3 hours that we just end up with expensive eye garbage.