Just for comparison here's what DLC has been like for other Nintendo games,
Mario Tennis Open: Yoshi's and Metal Mario QR codes.
Fire Emblem Awakening: Extra characters and levels.
Animal Crossing New Leaf: Various DLC items distributed monthly.
New Super Mario Bros 2: New mode with new levels included.
New Super Mario Bros U:New Super Luigi U.
Kirby Triple Deluxe: Dedede's Drum dash deluxe and Kirby Fighters deluxe.
Steel Diver Sub Wars: Various subs and Premium mode.
Rusty's Real Deal Baseball: The mini-games.
Mario Golf World Tour: More characters and courses.
Mario Kart 8: More characters and more race tracks.
Tomodachi Life: Various DLC items distributed for half a month each.
Hyrule Warriors: New story mode and levels, plus costumes for some characters.
The 3DS itself: The theme shop and its various themes.
Super Smash Bros for WiiU/3DS
at the moment) Mewtwo(1 character),Miiverse stage(1 stage),Tourney mode(1mode)
Smash bros currently has the least amount of DLC (except for maybe Mario Tennis Open) out of all the games at the moment. Just do some more DLC characters
(maybe
). Then maybe do some more stages, New Pork, Sector Z, Summit.