Unlike "Bolt" and "Zootopia", Disney tried again another musical, i.e., people singing instead of talking. That apart, unlike other Disney musicals, e.g., "Mulan" and "Tangled", the songs in this film are very repetitive. I lost count of how many time the main character's song is reprised, with maybe slightly different lyrics every time, but I stopped caring after the second one. The explorer's song, one of the few with Polynesian language thrown-in and that doesn't sound like a cheap Western European cartoon musical, is somewhat "fine", although also repeated unnecessarily too many times. Maui's and Tamatoa's songs are happily jazzy and unfitting with the film, but helped me to survive till the obvious ending.
Yes, the ending is squarely obvious after the first few minutes, just after the story of Maui's deed is told. The producers tried to make it less obvious by hiding the spiral on Te Ka's chest, but it's a Disney cartoon, who couldn't tell that Maui would come back to help (actually, who couldn't tell he would eventually ditch Moana in the worst possible situation, just to raise the "thrill"?), who couldn't tell that it would be Moana to fix everything (and not Maui, despite all his godly powers), who couldn't tell that it would have a perfectly colossal happy ending...?! Even the only character to die returns Obi-Wan-Kenobilistically to help Moana (what just makes sense, I guess, as Disney now owns the Star Wars franchise). Seriously, spoilers? Disney created a type of film which makes all spoilers simply meaningless (like, who couldn't tell the ending of "Frozen" just by seen the poster, with the two sisters side by side?) Granted happy ending is not fun, at all (and no, watching "how" the characters get there is not enough nowadays for enjoyment, this is not opera, this is cinema).
Maui is by far the best character, but just like Indiana Jones in "Raiders of The Lost Ark", absolutely unimportant for the plot (except for stealing the heart of Tahiti, oops, "Te Fiti", which any other unrelated character could have done, any and everything he did was useless to change the course of the story). Maui's self-conscious line asking Moana not to start singing was funny, but the fun vanished swiftly as the songs restarted filling up the space where actual story should be. I have to regard Heihei, the chicken, funny, although fully useless, too (don't worry, if it wasn't there, the stone would have fallen in the ocean, and it would have returned it to Moana, just like it did before).
Why is Moana the main character? There was no need for the character to be female, unlike Mulan or Merida. For the plot, Moana could be a shrimp, it wouldn't make any difference. I guess Disney wants to sell more toys to girls, and that's all. According to psychologists, men have a need to outstand, women have a need to fit in (this is not Wikipedia, you look for the references!) Thus, boys take any crap you throw at them, as long as it has flashy LED's and makes a lot of noise. Girls are usually more picky, they use to choose what appeals to them somehow (even if only because "everybody at school has one"). Heroines have a better chance to sell them anything, I suppose, so there comes another female leading character. Do you doubt it? Disney went as far as making Maui literally label Moana as a "princess", what she vehemently denies, just to make it sink even deeper in the brains of the young. That's pure evil!
Talking about evil, why are the parents always the evil people that don't let the heroine be, well, heroic (or even have a little fun)?! It had to be the fun-funny-and-cool, sweeter-than-honey, always friendly/compassionate, knowing-better-than-the-parents Grandmother the one to help Moana. Granny inflamed her desire to disobey her father's orders, which almost got herself drowned, what was exactly what he was trying to save her from (what is also completely nonsensical, as the ocean for far too many times saves her and others from drowning, to the point I stopped worrying that any character could die). That was a very evil message, that anyone can be a better friend than the parents. Sure, there are bad parents out there, but that was clearly not the case, as he was trying to protect her. Disney poisoning!
The plot has so many holes (some of which I have already exposed) that the ending is almost detached from the rest of the film. For example, why didn't the ocean simply return the stone to Te Fiti, why did it need a human to do the job? Moana wouldn't be able to do it without the help of the ocean, which opened a path to Te Ka.
The background message, "don't mess with Nature", was weak, far below "Mononoke Hime" or even "Over The Hedge". It's absolutely unbelievable that this film got such high scores. Those scores tell much more about the "status quo" of contemporary society than the film's quality.
Why do I bother coming here to blemish this film? Because it's an evil film, by an evil corporation, watched by too many children out there.