Nintendo has dominated this generation, but I'm not sure it will dominate the next.
The Wii has sold phenomenally well, but the same cannot be said for Wii software: the only Wii games that have sold a truly spectacular amount of copies are Wii Sports (bundled), Wii Play (bundled), Wii Fit, Mario Kart Wii, Wii Sports Resort (bundled), New Super Mario Bros Wii, and Wii Fit Plus. Of these, the only two games that make use of Nintendo-specific characters and intellectual property are Mario Kart and New Super Mario Bros: in the next generation, Sony and/or Microsoft will be able to easily come out with clones of the various sports minigames to be available at console launch.
If they do this the only way Nintendo comes out on top is if they 1) come up with a new game-changing innovation or 2) continue to be viewed as the "definitive name in gaming" by low-information consumers. The first seems unlikely, and I'm not sure that low-information consumers are the ones who drive most console purchases - if Husband X can make a convincing case to Wife Y that the PlayStation 4 is just as good for sports-related minigames as the Super Wii will she really insist on the latter console?
