Board Thread:Super Smash Bros. Discussion/@comment-14355010-20150106155005/@comment-26024036-20150413161034

DarKingdomHearts wrote: Ridley is already a stage hazard. I don't think stage hazard and AT's can be promoted to playable. If it was on-disc then it wouldn't matter but downloadable is a whole different story. (I love Ridley though, I wanted him in too)

You have to remember that Link is also in a stage, but he is still a playable character.