So! SSB4 is on its way and It already looks like certain stages are going to be 3DS exclusives.
Example:
Other 3DS only stages.
Battlefield (Peaks)
Gerudo Valley — The Legend of Zelda: Ocarina of Time 3D
Spirit Train/Spirit Rails — The Legend of Zelda: Spirit Tracks
Arena Ferox — Fire Emblem: Awakening [1]...
3DS Exclusive Stages.
Example:
Other 3DS only stages.
Battlefield (Peaks)
Gerudo Valley — The Legend of Zelda: Ocarina of Time 3D
Spirit Train/Spirit Rails — The Legend of Zelda: Spirit Tracks
Arena Ferox — Fire Emblem: Awakening [1]...
3DS Exclusive Stages.