That websites a bit quick to jump to conclusions.

;
Clearly they are counting the Wii version as the 5th, and they want to get a new team together to start producing the 6th next year. ~ and if they're just starting development and programming soon I highly doubt the game will release next year seeing as the current smash bros has been in production the past 4ish years, before the release of either handheld it's played on.
But it's cool that we know there will be another game, and that 3D and motion control is aimed to be a part of it. ~ Might seem a silly thing to point out but when you consider SSB seems to be a once a generation game and that Nintendo wants to make it's next console a merge of home and handheld console this could confirm it'll be 3D again ~ which if it's par home console might mean they're banking on 3D tvs being around for future gaming. =D