I know it's popular these days to point out sexism in everything, but was it really necessary to mark the 25th anniversary of Disney's Little Mermaid that way?
It was sexist of Ursula to tell Ariel she didn't need her voice cause men don't like women that talk, but you know what? Ursula is the bad person in this cartoon, her actions are supposed to be bad and reflect reality in which you will get ill-fated advice from people who are not really your friends.
Ariel making huge decisions at 16 is not going to make girls think they are fit to make such decisions themselves, girls at that age, even younger, already came to that conclusion on their own. It's called being a teenager.
Ariel having a perfect body falls under different category of problems, considering even Eric is a hottie, so you can't really talk about it being sexist if it strikes at both genders.
Ariel gave up her life under sea in favor of living with Eric and that somehow will make girls believe that it's up to them to make compromise in relationship... if I remember correctly, Eric can't live under water, so the other way around can't work. Also, there is nothing stopping her from visiting her family from time to time.
Would you rather have the original ending where she kills herself after being rejected?