According to the game's lead developer,
Masahiro Sakurai, development on the game had not begun at the time of its announcement, and would not begin until the completion of Sakurai's other project,
Kid Icarus: Uprising.
[2]
For the 3DS version, Sakurai wants it to be more of an "individual" and "customizable" experience where, hypothetically, the player could take a customized player and upload it to the Wii U version.
[3][4]
Sakurai commented on the possibility of including
Capcom characters in this iteration of the series, saying that "[he] can't say that it's entirely out of the realm of possibility that some Capcom character could appear in the next
Smash Bros. The big problem, though, comes from the idea of trying to get characters from a completely different universe to fit with the style that has been dictated by Nintendo's characters in a fighting game."
[5] The balance of the character's power was previously only measured by Sakurai, but he will involve his staff more in this game to make sure the characters are competitively balanced.
[6]
In September 2011, a photo of a supposed leaked document suggested a possible title as
Super Smash Bros. Universe.
[7] However, Sakurai commented that he was still working on
Kid Icarus: Uprising, and that work on the new
Super Smash Bros. game had not started and would not until after the former was complete.
[8]