User blog comment:DerpyDoodle/On the Legitimacy of the Leaks/@comment-32390199-20140903210050/@comment-24529455-20140904114535

It just wouldn't be logical to have Isabelle both as a playable character and an Assist Trophy. With that logic, Waluigi, Dr. Kawashima, Color TV-Game 15, and more could be playable.

Hmmm, playing as Color TV-Game 15 would actually be pretty fun.