This is fascinating news. To be honest, the mobile thing is less interesting to me then the other tidbit they threw out.
There's a bunch of articles online now from "journalists" talking up which games will be going to mobile now. Nintendo is not that stupid. Here's how I see it play out. DeNa will develop brand new titles using Nintendo IP which will be fun and short and push people towards "if you like this, you need to get the full titles on our console and handheld". This is a side thing to make a quick buck and advertise their main projects, their hardware. This is not to say they can't be fun but that is all I see them being.
The new hardware, currently called the NX (which is a far better name already than the Wii U) is interesting in it's timing. They teased a reveal of the tech next year, which would suggest E3 reveal leading to Christmas 2016 launch. This would give the Wii U a 4 year life span, short enough that they can get back into the game quickly while not being too short to hurt them in the eyes of the public or retailers ( or 3rd party publishers if they existed on the format), a mistake Sega made a number of times. I think the Wii U will end up being looked at in a similar vein to the Dreamcast (though less so) in that it will be a machine with a great library which no one bought at the time.
