Every single touch-centric game that made the DS huge should already be on mobile. That should just be the new platform for those types of games, because that's where the audience for them is now. Brain Age, Professor Layton, all that jazz. The people still gaming on dedicated handhelds are playing more "gamey" games that require physical controls, so those are the types of games that can stay on consoles.
The fact that Nintendo hasn't done this already shows how stubborn they are. They could have an install base of hundreds of millions, but they're only interested in selling a game on their own platform on their own terms.
Last thought, Animal Crossing would be PERFECT on mobile. It's exactly the kind of social game that's been huge for years now, and all of it could easily be done with just a touch screen. It could be free or even a couple bucks, and you can either unlock everything yourself, or the impatient types can pay to get tools faster, get furniture sets, make stuff grow faster, etc. It would be the perfect situation where the average person doesn't have to spend to have fun, but Nintendo can still make a lot of money from it.








