I believe the episode was called "Power Ponies". If not, forgive me, my memory is failing me! I know that My Little Pony is a show for children as well, but man, was that episode so...un-dark (how technical of a term!) and anti-climatic for an episode revolving around an alternate universe which contains superheroes. Even the ponies themselves...their powers, in my opinion, were a sort of...let down.
If I were in charge of that episode, I would have made the Power Ponies and Mane-Iac more...cool, and I would have made things more climatic and...a bit more dark!