No new F-Zero or Earthbound stage? I mean I know we got new ones in the 3DS version but still
Anyways let's see what we got.
Certainly legal are: Battlefield, FD, Lylat, Smashville, Town and City, Haliberd, Castle Siege
These were all legal in Brawl (+town) and assuming nothing drastic has somehow changed about any of them they should be fine now too.
Very likely legal: Duck Hunt, Pilotwings, Delfino Plaza
Delfino was a fringe case in Brawl due to Metaknight. The other two are hazardless but new so it's hard to be 100% sure on them but it's pretty likely.
Likely legal: Skyloft, Wuhu Island
These stages look good but are brand new so a bit of playtesting would be nice just to be sure. Even if every stage below this isn't used, we still have 12 stages.
Possibly legal: Big Battlefield, Kongo 64, Pokemon Stadium 2, Norfair, Windy Hill
These stages possibly might not be legal due to the possibility of circle camping or maybe the hazards are too disruptive, but they don't seem so bad that they can be written off yet. Definitely needs testing to make sure.
Neutral Walkoffs: Mario Galaxy, Coliseum, Wii Fit
These stages are totally neutral, but are walkoffs which are always controversial. They're worth giving a good look at now especially since there are no chaingrabs and projectiles have mostly been tuned down in this game.
Maybe: Mario World (gotta test nabbit firsthand), Mario Circuit 8, Luigi's Mansion, Jungle Hijinx, Port Town, Wooly World, Orbital Gate, Kalos, Skyworld, Gamer, Garden of Hope, Wrecking Crew
These stages are probably controversial enough that if they are legal they won't be more than counterpicks. Still worth testing though for sure.
Not so neutral walkoffs: Mario Circuit Brawl, Bridge of Eldin, Boxing Ring, Onett
Very likely to be ignored, abut the hazards on these stages aren't actually that bad, and if it weren't for the walkoffs these stages would probably have a better chance.
No: Temple, Ridleyland, Yoshi's Island, Great Cave, Flatzone X, Palutena's, Gaur Plains, 75m, Wiliy's Castle, MS Paint land
Just no.