Flip Flop of God: Wordof God stated before that, because of its release date, there was not going to be a Wii U version of The Power of Two. A few months before the game's (and the system's) release, it was announced that there is going to be a Wii U version.
What Could Have Been: Gremlin Prescott was, at one point in production, planned to fall to his death, and the red button on his glove was conceptualized as a "self-destruct gag". Concept art has also shown the Mad Doctor's boss battle taking place on Mean Street, and gremlin houses, implying Gremlin Village was a planned area.
Other concept art indicates the Ventureland pirates sidequest was going to be a full-blown adventure with Mickey helping in their battle against Blackbeard.