Great analysis on sidekicks and Disney princesses. That's true that for the most part, the comic reliefs contribute to the plot, which makes their presence significant, and a lot of them have been shown to have dramatic sides too, so they're more than just sidekicks - I'm referring to this term based on how these characters are labeled by general viewers. I think the negativity comes from viewers who find the lead characters to be the most important that anyone other than the leads would be quickly dismissed.
I agree that it has breathtaking animation. Just bought the deluxe edition soundtrack. Surprised all the deleted songs are equally catchy, some even more than the ones used in the film. "I Seek the Truth" and "Home" are amazing.