Nintendo has released an update for Super Smash Bros. Wii U. Currently it seems this update is only available in Japan but I would assume to see the release in other locations soon.

Update 1.0.2 adds 15 additional 8-player stages to the mix and some slight changes to those stages.

【通常ステージ】 Regular stages

マリオサーキット（X）/ Mario Circuit (X)
ルイージマンション / Luigi’s Mansion
パイロスフィア / Pyrosphere
ノルフェア / Norfair
ライラットクルーズ / Lylat Cruise
ポケモンスタジアム2 / Pokémon Stadium 2
村と街 / Animal Crossing / Town and City
すま村 / Animal Crossing / Smashville
Wii Fit スタジオ/ Studio Wii Fit

【終点化ステージ】 Final Destination stages

マリオギャラクシー / Mario Galaxy
マリオサーキット（X） / Mario Circuit (X)
洞窟大作戦 / Kirby : The Great Cave Offensive
ライラットクルーズ / Lylat Cruise
ポケモンスタジアム2 / Pokémon Stadium 2
村と街 / Animal Crossing – Town and City

Stage Changes

Mario Circuit – lacks shyguys
Luigi’s Mansion – Can’t be destroyed
Pyrosphere – lacks ridley
Norfair – no lava at all
Lylat Cruise – no ships flying around
Pokémon Stadium 2 – lacks stage transitions
Town and City – All background characters removed
Smashville – All background characters removed (cept petey, he stayed at a slow framerate)
Studio Wii Fit – no mirror background

Link