Wait, what?! A fat unlikable woman doing bitchy unlikable things while no one laughs?!
And you didn't suggest Malissa Mccarthy?!
Come on man, its like she was born for this roll! This is her calling! The natural progression from unlikable protagonist to unlikable antagonist!
JoAnna Garcia Swisher played Ariel in Once Upon a Time and she kinda nailed it IMHO. Say what you will about the shows convoluted writing, but they have some great casting picks for a lot of the Disneyverse
"Little Mermaid" will get a live action movie sooner or later. And I just read that Emma Watson will play Belle in live action "Beauty and The Beast". Such a waste. She'd make a better Little Mermaid and Emilia Clarke would be a better Belle. Oh well.
If a live action Little Mermaid was done why not cast the lady who is Ariel for the play? As in the original play... Sierra Boggess. She has the most amazing voice, she is absolutely gorgeous, and is perfect for it!