Nintendo has done just about all they could do with the Wii U except Zelda. And that isn't going to just magically make the system fly off the shelves for a long period of time and chance it from failure to success. No single game can do that.
Their is zero hope left for the Wii U. It is dead. And Nintendo knows it. That's why they are shifting their focus to NX.
And their main priority should be to learn from the mistakes they made with the Wii U, (and 3DS, because the 3DS didn't get off to hot start either.) So that they can ensure that the NX gets off to a very hot start right out of the gate and execute its concept perfectly so that it'll sell immediately. Drop the Wii/DS brand entirely. Give it a different name (personally I'd prefer the UNES - Ultimate Nintendo Entertainment System. I'm hoping for that Fusion concept to be true as well, because, it truly would be the Ultimate Nintendo machine, hence, Ultimate Nintendo Entertainment System.) Bring 3rd parties back by having the architecture and power similar to Sony and Microsoft's systems. Strong Virtual Console library. Extremely affective marketing campaign.
As for Microsoft. Next year is looking very grim for them, seeing the lineup that the PS4 has for 2016 with Uncharted IV, Persona 5, The Last Guardian, and now Sony and Activision are buddy-buddy with Call of Duty being marketed under the PlayStation banner.
They could do another price cut, if they're willing to lose money on each system sold, but that won't do much seeing as how throughout the year up to October, the Xbox One was $50 cheaper than the PS4, and the PS4 still outsold it, very comfortably might I add.
Really, Sony has had this generation on lock down since E3 2013. There isn't anything Microsoft can do to have the Xbox One catch up with the PlayStation 4.
What they CAN do however is build up the 1st party lineup, catalog, and development so that Microsoft's 1st party output not only eclipses Sony's but can even rival Nintendo's.
Because, all of the things I mentioned earlier about what Nintendo needs to do to get back in the game. Microsoft has already done it, (except the much rumored "Fusion" concept since Microsoft doesn't have handheld.) The only thing they are lacking is the very strong library of 1st party Intellectual Properties. And I gotta give credit to Phil Spencer and the amazing job he's been doing. That's what they appear to be focusing on. They already have Halo and Forza, Gears of War is coming soon, ReCore is new IP that looks great, Fable is another great one. But they need more. They need to keep building it up. How about a 1st party platformer? A 1st party fighting series?
Since both the PS4 and Xbox One share a lot of the same 3rd party games, if not all of them. It will ultimately come down to exclusives -not Timed Exclusives like with Rise of the Tomb Raider. Actual, real, legitimate, 1st party exclusives.
And while it won't do much to help the Xbox One's fight with the PlayStation 4.
What it WILL do, is build up Microsoft's reputation as a great 1st party developer. Which will greatly help the Xbox division in the long run.
Think of it like this: Whenever the PlayStation 5 and Xbox....4...whatever they call it, are about to be released. They all share similar specs, hardware, and architecture, and they have the same library of 3rd party games. The same price tags as well. So what's the next BIG thing that the gamer and customer will look at? Exclusives. They look at Sony's exclusive lineup and see how it stacks with Microsoft's, and they see how much bigger and better Microsoft's is, assuming they go that direction. That will be the clincher, right there. And all those sales that Microsoft lost the PlayStation 4 the prior generation, they will have gained them back.
Just like Sony gained them back with PS4, after they lost them to the Xbox 360. And how did they do it? Exclusives, exclusives, exclusives. Uncharted 1,2, and 3, the Infamous games, Gran Turismo, God of War, Sly Cooper, LitteBigPlanet, MLB The Show series, the Last of Us, the list goes on.
Games still sell hardware. And when the 3rd party games are on all systems. Then it's the 1st party games that will push on ahead of the other. And THAT'S what Microsoft needs to do. Build a strong, diverse, great library of 1st party titles.