The balance board has a huge install base.  Wii Fit pushed the board into a lot of homes but it failed to keep the momentum up it had at launch.  Nintendo really needed to make Wii Fit a money maker and milk it for all it was worth.  It has a lot of potential to constantly bring money into Nintendo.

- Add DLC on a bi-weekly/monthly basis

- Give the ability to skip past the weigh in so anyone can play the mini games at any time they want.  This would open the "game" up to being more of a GAME.

- Add in some local multiplayer modes

- Add in some online modes such as the ability for friends to connect and work out at the same time.  

You can already skip the weigh in.  You could since the first one I believe, and definitely in Wii Fit Plus and U.

Just downloaded Wii Fit U the other day and wanted to let my daughters have some fun on the balance board. I spent 15 minutes setting things up in the game and still couldn't play. It was way too long and ruined the experience. You have to link an account to the game before you can do anything. You should be able to just get in and play without using an account. I shut it off and gave up.

Dunno about on Wii U but the original Wii Fit you could just use generic characters and get straight into the games.