According to 1PStart, Masashiro Sakurai, director of SSBB, revealed in an interview with the radio in Japan, 3 new characters for the series, aswell, with the removal of other 3.
- Bowser Jr.
- Link from Wind Waker
- Ridly (Samus’ arch-nemsis)
- Mr. Game & Watch
- Young Link
- Ice Climbers
So that also means, that all the other characters like Mewtwo, or Falco, etc, will continue here, aswell as the previous announced Meta Knight, Zero Suit Samus, Wario, Pit and Snake.
Source: Here and Here (spanish)