Aside from the new Smash Bros Wii U and 3DS screenshots that Sakurai has been sharing on Miiverse, we haven't heard a great deal of detail about the games so we've all had to watch the trailer repeatedly to glean as much information as possible . We've already taken a closer look at the Smash Bros characters but now I'm focusing on the stages, having compiled a list of the stages we know of, along with a little bit about how I think they could work.
First up, is a stage based on Skyloft from The Legend of Zelda: Skyward Sword. It looks like the fighting platform zooms around the sky, taking in different parts of the town in a similar fashion to Delfino Island in Brawl. Hopefully the stage changes up a bit throughout the fight - I'd like to see the Sky Keep take shape.
Now we have a Smash staple; the Battlefield stage. The stage has been given a graphical overhaul and looks gorgeous. It looks like the time of day can change on the stage and it uses the same tried and tested three small platforms and one main platform system. Battlefield was always a favorite amongst my friends because of its simplicity and it looks like that has been maintained for Smash Bros 4.
Here's the Legend of Zelda: Spirit Tracks stage. This stage is a 3DS exclusive like the other stages from handheld games. It looks like it would be super hard to launch people upwards with those roofs there. Maybe if you knock your opponents off the train then they'll just get left behind like Big Blue in Melee in Brawl.