I'm hoping this is a channel, or an improvement of the Wii Fit channel rather than a new game.

I suppose it would make sense to release a Wii Fit Plus game to the 17million+ install base they've created for the balance board... And release a seperate Wii Fit Plus bundle to drive further adoption of the device.

http://www.eurogamer.net/articles/wii-fit-plus-mario-zelda-to-be-shown-at-e3-report_1

It's looking more and more likely Wii Fit Plus will be given time at the press conference.