I honestly think the main thing that has kept them above the rest is Mario. As long as they have a 2D Mario with every console title, they'll win every generation console war. They might as well launch Wii 2 (or whatever it'll be called) with 2D Mario again, just add a good enough selling point to it. Everyone listens for Mario, so even if its just a bunch of tiny buffs it'll be enough to keep them buying. Along side that, Pokemon, Zelda and Metroid give them the hardcore buff they need to pretty much have everything gamers are looking for. Concerning the Wii, they just need more Starfox, Donkey Kong, F-Zero, Kirby, Fire Emblem and Yoshi-strict games to mix it up a little better for us.
They're doing fine with the DS with plenty of everything, their core franchises, and more.
