Yeah excatly, Miss. Piggy playing the part of Dorothy for a little comedy skit totally works fine.
But Miss. Piggy is not only a grown woman, she's also a really stong grow woman, where as Dorothy is protrayed as a young and pretty helpless little girl. Since they wanted to make an made for TV movie that's can be somewhat close to the original having Miss. Piggy play the part would of been an awful idea, I mean who would buy Miss. Piggy being in trouble by an old witch hag,
, the woman been known to bend metal bars,
, she's far from helpless. I liked the idea of Miss. Piggy playing all four witches much much better, it plays with her mean side just as much her sweet side.