I love the Little Mermaid, but I never think it works well on stage. The Broadway version, or other non-Disney versions of the story, there is always an issue with recreating the swimming. No matter how hard they try, theater is not the medium for under water scenes.
The music screams 'I am a musical' or 'I am theater!', but the subject it not really suited for this medium.
The Broadway had the issue that they tried to make Ursula a comical character and her costume, while beautiful restricted her from being scary as she could never could get close to Ariel.