Ya I would say that Wiifit is a high risk project. But it's the kind of risk that if successful, increases Wii momentum. Nintendo could stand to lose lots buy could stand to gain much more.
Also I think it was MrStickball that mentioned Alan Wake. This is actually one of the titles that interests me. I will definately check it out. It might do well enough on PC to turn a profit, however I doubt it will make a profit on the 360 alone.