I know that this has been a debate for awhile but I was thinking about it and it might be the perfect time for them to reach a broader audience. I have been a Nintendo fan since the days of the NES and used to be against Nintendo making games for anything other then a Nintendo console but times have changed now. If Nintendo were to become just a software developer for both MS and Sony then they would get the gamers that don't want to buy a Nintendo console to play their games (Which is a lot of people) and they would get the Nintendo fans as well because they would buy either an Xbox or a Playstation. They would save money on R&D by no longer having to invest in making new hardware (Which has been lacking the last 2 generations anyway).
I myself am not impressed with the Wiiu and I bought mine at launch. They have lost all 3rd party support and now just 2 years in and they already announce they are working on a new system. Unfortunately for them I will not buy a Nintendo system at launch ever again. This new one will have to be mind blowing and knowing Nintendo it's just going to have some kind of controller gimmick and be underpowered.
So my question is why shouldn't they become just a software developer? At this point it seems like only the diehard fans are going to buy their products and moving into cell phones may bring in some new revenue but honestly what gamer plays cell phone games?