User blog comment:AlexSmasher/Mewtwo just proved something/@comment-10885667-20141028161822/@comment-5185663-20141030030347

Sakurai stated in a famitsu interview that elements from Melee are too old to carry over and that all characters in the game were worked from the ground up. Doc took less time because he was worked from SSB4 Mario.

I'd love to see additional characters join as DLC, but Mewtwo alone is fine for me. Because if Nintendo went too overboard with DLC, then half the magic of seeing SSB5 in however many years it takes wouldn't be as exciting.