I make no mistake that I think the Wii U is headed for a lot of trouble, especially this year. I'm not sold on a lot of the Kool-Aid that Nintendo selling this time around.
So from this POV, where not all things are raindrops and lollipops in the world of Wii, what would I suggest Nintendo do? A few pointers that I think are more out of the box, but I think are ways for Nintendo to carve out their own niche.
1.) Idiot Proof Your Marketing - Your marketing ... sucks, Nintendo. OK. So what's the quick fix here? Hire a spokesperson, someone who can be the face of your product. I would reccomend either Megan Fox or Kate Upton. Regardless of what you think of them, they are well known, attractive, and can more easily position the Wii U as the "hip" and "Hollywood cool" console. Just show their day, in their trendy LA or New York apartment, watching Netflix on Wii U, then switching to play some NSMBU with a friend, then turning on the Youtube channel and laughing at a video -- there simple. A campaign like this will also get attention on things like Access Hollywood and Entertainment Weekly.
And indirectly this is smart marketing, but aligning the Wii U as the console of choice for an attractive model/actress, it's kind of a slap in the face of the stereotypes that games are for nerdy male teenagers/college guys or little kids. It's how Apple would market.
2.) Screw Third Parties -- There I said it. You will never win in a race with Sony and MS for the traditional third parties. So why keep competing in a race you can't win? Change the rules. Start investing more and more directly into small, low-risk indie developers, especially from the West, like the Trine developers. Go find the next Angry Birds or DOOM, it's out there some where with 6 guys in a garage. Go find them. Continue to develop more alliances with Japanese developers like Platinum Studios. Work with Mistwalker again (The Last Story wasn't bad, just released way too late in the Wii lifecycle). Pick up Itagaki's "Devil's Third".
3.) Create (or buy) a flagship "hardcore" character IP -- Mario paves the way for a lot of the mascot/cartoon/license based content that floods Nintendo consoles, but Nintendo really doesn't have a similar beacon for the older audience. You could always let Retro try their hand at a new IP, or go find one to publish. I suggested for risk-averse Nintendo to approach the folkes at Danjaq/EON productions, who own the James Bond license. Bond is cool, Bond is easy to market, if the rights are available, perhaps Nintendo could get them (or perhaps just rights to Bond FPS games). A Bond game with the same effort put into it as a Mario or Zelda would sell an easy 3-4 million and then other developers could look at that and say "oh, I guess there is an audience for something edgier here after all".
4.) Get In Bed With Square-Enix -- Screw Kingdom Hearts, a Nintendo-Square-Enix RPG has long been hypothesized ... but it would also make a lot of sense. And sell a ton of software and hardware potentially. Contact Square-Enix, I think they would be very interested, but it should come at a price. Final Fantasy VI and VII Remakes for 3DS and Wii U. The Wii U in Japan needs a killer-app from a third party, and no, sloppy second Monster Hunter ports and an MMO Dragon Quest don't cut it. A Final Fantasy x Nintendo x Dragon Quest game (gulp) would sell millions and millions. Some fanboy fantasies are silly and stupid, this one just makes sense.
5.) Consider A Controller Re-Design -- No big deal that handhelds get redesigned every year or two ... so why not the Wii U pad? The current version is too bulky and quite frankly a bit ugly with poor battery life and a so-so screen. In a year or two, maybe consider making a sleeker Wii U pad with a larger battery and a better quality screen. If this thing is supposed to be in everyone's living room and even their defacto TV remote ... it needs to be less of an eye sore.