Analyst: Mario on Mobile is Coming

Nor should they go multi-platform. I don't want to play Mario 3D World on a PS4 or Xbone.

However, their back catalog is ripe for milking on many, many platforms. They are a big company. You wouldn't think it would be so hard to make the Virtual Console a competent piece of software. Get some people in. Make the Nintendo Virtual Console a separate 'Steam'like' entity.
Buy a game on one platform, and own it forever, install in on all the NVC supported platforms you own (what a revolutionary concept).

Make the NVC cross platform on PC, Android, iOS. Give them official retro SNES/N64/GC controllers. Who wouldn't buy!? Even with the absurd VC prices they currently have. Would minimise and monetise much of the Nintendo PC emulator scene.

They should do special add-on apps that could connect to the games such as a level editor for super mario games or something. This could help.