Warioware and rhythm heaven are the most obvious games for mobile as they fit perfectly. I loved r.heaven on the ds and I think people would like it, you can play 5 min or 2 hours, it's addictive and fun.
Also, one of the biggest dissapointment I had with the wii u, kirby, would be perfect for mobile as well. I loved how the game looked but I couldn't stand the gimmicky gameplay so I had to pass. But that game fits on the mobile market more, maybe not as a full game but imagine the same mechanics only with changes like shorter levels or focused on defeating enemies and bosses or collecting some specific items.
Nintendoland also had perfect ideas that could work as small mini games for mobile.
I think what Nintendo should do is focus on the way people play on mobile, how playing on mobile is as opposed as a console (tap the screen, move the phone in a racing game etc) and then create some unique games on their own, with their ip's.
They could do so many great things. Also, miitomo I think could be great. I love mii's and if they do it right they could make billions.
