I beg to differ. In the original story, while she does fall in love with the prince, the main reason she wants to become human is just so she can have a soul. That right there makes a statement about the character.
And yet that story
wasn't sexist? A girl who has to give up her voice and walk on daggers just so she can get a soul? And the only way she can
get a soul is from the love of a man. I see no difference. Sure, it's "deeper" but it would still have sexist connotations. Not to mention it would specifically target a religious audience, which I don't think is Disney's purpose to do.
Besides, Ariel wanted to be part of the human world long before she met Eric. Eric was not the motivation of her deal. Her longing to experience humanity and her disputes with her father were her motivation. Eric just happened to be there for her to fall into, where she fell in love with him.
And I really think that something is only sexist if you are looking for it. I mean, would
Pinocchio be sexist because he couldn't be a real boy without the help of the Blue Fairy? Why can't you just think that characters, boy or girl, make choices with which their genders have nothing to do with it?