It is likely that the recently released Super Smash Bros 4 for Wii U has a secret character. This was suggested by the hidden dialogue in the game.
Palutena's Guidance has a dialogue that is activated when Pit down-taunts Palutena Temple and it will also carry a conversation on Pit's opponents. However, Gameranx found one conversation that did not go with any of the characters.
Pit: Who is that?
Palutena: I have no data on this fighter. I can't believe it.
Viridi: It must be an intruder from another dimension.
Pit: Whoever it is, the goal remains the same. To fight and win.
It was reported that this dialogue is heard in a match with a DLC character and Masahiro Sakurai, director has said Mewtwo will be the only DLC fighter that the company has planned. This dialogue speculates the possibility of more DLC characters.
No Balance Patches for Wii U
Sakurai, in one of the interviews in Famitsu magazine (via EventHubs), said that Nintendo does not have any plans to balance the game with more patches. He, however, said that players can expect more fixes for the online play, but he added that the company will address any "glaring issues."
Meanwhile, he, Rosalina and Luma Amiibo will be exclusive only to Target, the retailer. These Amiibos will be part of the Wave 3 in 2015, according to the Escapist.