I found the following video to be interesting and timely as I attended a Little Mermaid sing-along last week.
I do wonder if Disney is really at fault or if it's our cultural mythology in general. Most of the stories are part of our folklore or were fairytails in other countries adapted by Disney. Yes, they provide the imagery, but the basis for the story provided much of the masculine and feminine rolls.
... And yes, this time around, I did notice how mega-buff King Triton was and how impossibly tiny Ariel's waist was.