Spend the actual money to be the TOP console dog once again, like they used to be in SNES (...N64) era. Spend the actual money to get all/most of the 3rd party games onto the Next N. The Wii was quirky enough, and I would bet big bucks that they spent R&D money researching motion control, that it won big time, but such things are massive hits or misses.
Traditionall Nintendo wins because they have _all_ the games. Nothing more, nothing less. Mario whatever, Zelda, Metroid? Don't mean shit if its not backed up with all the other 3rd party games.
I would mount a massive offensive to put together _the_ strongest 3rd + 1st party lineup for the entire generation and I would plan that the console has a long life. Not necessarily an absurd 10 year lifespan like PS3/PS2 had, but the Wii had like a massive buildup over 5 years then colapsed like a stack of dimes. I would basically strive to finsih the gen off strong with the best games at year 6 or 7.