Great Concept
Great Execution
Exceptional Software (for its niche)
It may need to diversify a bit to keep the momentum, at this rate I see it blasting to 40-50m with Pokemon and the like but slowing down once this core audience is satisified. Hopefully the Japanese developers come through in 2018 and beyond and Nintendo employs the blue ocean strategy whilst still keeping their eyes firmly on quality experiences which core gamers can enjoy too (so no cheap cash in or wii music's type games)