Alright, this situation with the WiiU is more complicated than some are making it out to be, and the slow sales are not necessarily related to the poor 3rd party support and vice versa. A large issue with the WiiU is that is lacks a piece of "ethos" software, so to say, what the WiiU lacks is what Brain Training was to the DS and what Wii Sports was to the Wii. Ethos software is the kind of software that reveals the heart of a console, that represents the philosophy behind its inception. For the Playstation, this was Final Fantasy VII and for Xbox, Halo. For this reason, I don't believe the WiiU is entirely doomed and can be revitalized, like how Brain Training (and the DS lite upgrade) .
And I don't believe that Nintendoland is a piece of "ethos" software either. It's far too steeply entrenched in the language of Nintendo franchises past, and the language favors nostalgia over progress. Now, I'm not going to try and predict what kind of software is going to come forward as the "ethos" game. I'm not even sure if it will come out at all, BUT there are ways Nintendo can approach their console and software woes.
1. Drop the Price
Sucks, but it has to happen, at least $50 USD. $300 USD is a great entry price for the premium package. Line up the price drop as close to announcement as possible. Line up the price drop before competing consoles enter the marketplace. Make sure the mainstream media knows all about it. Line up marketing with the price drop. Don't mention it as a "new low price". Get rid of the "basic" package. Whatever the gen 6 consoles cost, they won't be able to match $300+game+controllers and first gen games won't look significantly better than WiiU offerings. Drive the point home.
2. Give up on AAA
Honestly? AAA game productions are laced with politics, design-by-committee, and shittons of pre-conceived notions that are mostly wrong, entirely because they cost so much to make. The kinds of resources required to get companies to give Nintendo shoddy, late ports isn't worth the return. Nintendo is better off focusing on putting their resources into getting ports of up-and-coming "A" or "B" productions, such as CD project (say what you will about quality, but CDPR does not have the same kind of budgets games like Skyrim have, and thus freedom from corporate politics). A and B games were some of the most fantastic offerings on the Wii, from No More Heroes to Muramasa to Little King's Story. These were the kinds of games that drove the PS2, make them drive your console. That's not to say snub studios working on AAA games for Nintendo platforms, but if EA is going to be a dick and block WiiU development, don't stop them. Beat them. Make Mario American Football, and make it BETTER than Madden.
3. Port Unreal Engine 4 to WiiU and Develop Middleware Tools for Distribution
Okay, I know I just said avoid AAA, but UE3 had alot of presence in those desirable A and B releases. Giving studios the power to port to your system easily and with solid support makes releasing software desirable and Epic stupid for not doing their job in the first place. Making UE4 accessible on your console makes ports that much closer.
4. Court those Indies HARD
While the same old shit reigns in the land of AAA, independent studios thrive on bringing novelty and interest. One snazzy indie game won't beat out the competition, but each one will bring new people in and keep the dedicated playing your console. Just look at Steam. Yes, they sell a whole boatload of AAA titles, but indie games get almost a disproportionate amount of spotlight. Unity and web form support is awesome, but now you need to take it a step further. Call them, build relationships, make sure they can use your hardware efficiently. Commission a game from one of the more interesting up-and-comers and feature it on the storefront.
5. Your DDL Storefront is Gaining Popularity. Use it.
There is one incredibly powerful thing in having a full game storefront: Power over the shelf. Retail is a dangerous proposition for most small studios and publishers. If you're not popular, retailers won't stock your product, and that makes for a very difficult time selling to consumers. Nintendo games are largely safe. They tend to sell, so retailers stock them, but what about those A and B games? The more of them there are, the more they're competing for shelf-space. In order to reduce the financial risk, featuring promising games on the full-game storefront and putting them into consumer mindshare would allow non-Nintendo games to flourish where they might not have the mindshare otherwise.
Something to look into would be a sort of "rental" system similar to Steam's free weekends, where select games might be downloadable for a period of time for free or a small fee and would likely bring the storefront more mindshare.
This, of course, all assumes that a piece of "ethos" software will come up sooner than later. I feel that this would be the best way to create an environment for it. The focus on hollywood flash for the price they're asking is frankly unsustainable in the long run, with too many busts over booms. The best way to do this is to work like Nintendo always has: conservatively on the business end, but artistically on the product end. And most importantly, never assume you're going to win out.