When Wii wasn't been showed, there were rumors about a controller-touch screen, so every game could have its own buttons. Today, with millions of DS an Wii Nintendo should have a base from where returning to make things for [hardcore]gamers; but they cant give up casual gamers. If they will be able to make a console that still attract casual gamers but can be a good thing for others (for example:X360 for me and Kinect for my little niece ;D ) maybe they'll handle the business again in the next generation.
I believe Nintendo style is good, and dont need "adult games" (though I dont dislike them) One thing seems to be sure: their online must be revised.