I was liking the movie at the beginning, but as soon as the Mario Bros. got separated, and they were in the Mushroom Kingdom, it lost me. Sidelining Luigi for a near flawless Princess with nothing interesting about her-- constantly putting down Mario (the guy who's been saving her for countless games), bad voices for the Kongs (Cranky was unbearable), Bowser being too much of a Peach simp, all Toad's looking alike (reeks of a Miyamoto decision, like what he did to Paper Mario. Bring back Toadsworth!), and even Brian's score with the music left me wishing Mahito Yokota from Mario Galaxy would just takeover, and show how it's done. They didn't do a good job selling the themes that were established early of a Mario who never gives up, or a scared Luigi afraid to stand up for himself.
Here:
I agree a lot with this long video.
For a sequel, stick with the Mario Bros, please. Mario was at his best with Luigi by his side. Movie Peach sucks, she's a prick, humiliate her some and bring her down two notches, and maybe she'll start to be more relatable, someone to sympathize for, and potentially likable beyond the games giving her all her appeal. Bowser lost his mojo early in the first movie. I think he should remain a villain, but end up being a reluctant ally to Mario in a sequel for an interest that ends up aligning the two, for at least 1 movie. Then they go back to being rivals. A villain with a soft side. Or Bowser can be the big bad again, and redeem himself by being far more competent, out for revenge, and more in control of his Peach hard on.
I don't know what can save the Kong's when I just don't want to hear them at all. Keep DK and gang out! Put them in their own movie so I can skip it. Or better yet, just get better voices, man! I much prefer the direction Rareware was going for the character's voice.