Here's what I want to see with the next hardware(s).
One Platform / Multiple Hardware Configurations - One software platform and ONE library. By this I mean any game can run on the console or handheld ect. Just spec'd different to the device (i.e better effects and higher res on console, portability on the other) This would in addition, free up dev teams in between big games to try new things, like come up with new properties or resurrect dormant IP.
Universal Accounts - Everything tied to your NNID and NOT the hardware. Games, DLC, VC, and everything else is easily accessible on any device. This is all pretty self-explanitory.
Backwards Compatibility - All 3ds and Wii U games playable. All Virtual Console and digital goods carry over with no extra charge or upgrade fee. Of course this would all depend on the controller interface for next gen, if they keep dual screens or not ect.
I would be happy if the next console was PS4+ level of power at a sub $300 price tag. Graphics alone don't impress me anymore but I expect it to be at least that powerful with the 4DS(?) at about Wii U level seeing as mobile tech has come a long way in the last few years.
I also honestly don't major third parties are EVER making a return to nintendo consoles again, at least not the western ones anyway. I think they're better off improving their relationships with indie devs and more home grown 3rd party support like they had on the N64 to offer more diversity in their lineups.



