I think Nintendo needs to keep a close eye on the other consoles sales this gen, to help them get a better idea of how the market is shifting. The next years will be painful for the gaming industry, things are changing, cell phones, tablets, streaming services, digital distribution, all these things will shake things up significantly.
While Nintendo isn't going anywhere soon, they need to decide how they want to roll with this. My guess is they will stay a small company that will keep delivering quality games to their fans, trying to get healthy sales, but not achieving explosive growth. Wii and DS-like success will never happen again, phones and tablets will make sure of that, but they need to figure out a way to return to profitability, which is probably not going to happen anytime soon with 3DS entering its 4th year and Wii U doing abysmally.
As for Wii U, I don't think anything can save it, maybe a relaunch would help, but I understand that spending a significant amount of money doing it is a risky move. Unless a miracle like Wii Sports happens, they'll just have to keep launching great games like they've been doing to keep current owners happy.