It's true, Nintendo's really becoming an anomaly lately and it has me worried. Personally I love the Wii, they had a small burst of good games a few months ago with Sonic Colors, Kirby's Epic Yarn and Donkey Kong Country Returns but I don't even enjoy it mostly for that. I play my Wii almost everynight trying to get a Megalopolis in the SNES version of SimCity.
I think they'll have to change. And hard. Back when the Wii first came out nobody touched motion controls for quite a few years, but with the rise of cell phone gaming, the Move and Kinect, and the PS3/360 successors which I'm sure will incorporate something Nintendo's going to be scrambling new gimmick. To me, they have third party games but they're sub-par, and there aren't enough of them. Their systems bring the gameplay but when your next-gen console is just now bringing things up to HD... yeah, I'm very worried. There are a lot of reasons to be. And I even like the 3DS.
I want to say that gameplay > graphics, but Mario Kart can only stay fresh for so long.