It's probably fair to say most of us are looking forward to New Super Mario Bros U on our new console-to-be. One thing which could be considered a snag, is that in multiplayer games Mario and Luigi are joined by two generic Toad characters. This will continue to be the case, unless you choose to play as a Mii character. In an interview, Nintendo's Takashi Tezuka was asked why alternative characters like Wario or Daisy were not included:

Perhaps it was also easier to implement from a developer's perspective. If you've ever wanted to see yourself inside a Mario game, New Super Mario Bros U will give you that opportunity.