You know, I remember a little game...what was that called? Oh, yeah, Wind Waker, and when that introduced cell-shaded graphics, the most minor of departures, there was a sh*t storm. Seriously.
I think in a way, we want safe sequels. We don't want change. Or rather, Nintendo did change (motion, casual) and lots of people didn't like it. I think those people just wanted a Gamecube 2 instead of a Wii. If that had happened, oh boy....there would literally not be a Nintendo anymore.
If anything, I'm an older gamer (32). I'm married, have 2 kids, and my first was born the year the Wii came out. I think if not for the Wii, I would not be gaming anymore. I wouldn't want to play PS3 or 360 with my daughter or my wife. And I don't play online, because you need a whole lot of free time to really enjoy online play, which I don't have. And I tend to like the games I grew up with, which is why I love the 2D platformers. And I don't have the patience to sit through 30 minutes of tutorial missions in order to start having fun with a game, because chances are, I only have 30 minutes to game on a particular night anyway.
Oh, and I would never have been able to justify spending $300 on a console that only I would play. But $200 on something for the family?