Depends which one you want.
The ORIGINAL original had Sailor Moon style transformations, and an adventure arc would have lasted all of S1. Also Pinkie was originally a pegasus named "Surprise"… I am so glad they changed that second part.
More recently, Faust originally held that Nightmare Moon winning would have entailed all multicellular life on the planet freezing to death (much like taking away the sun IRL). Larson didn't like this much, and threw it out for that one episode that featured "bad futures"

Any examples?