The more realistic route to a recovery (not a renaissance!), is that Nintendo's big hitters- Mario Kart, 3D Mario, and Smash- resonate with a decent amount of the Wii userbase and along with a price drop allow for a relatively healthy userbase and lead to decent Japanese support and a decent ecosystem for software.
I'm not talking selling 100m consoles- I'm talking selling 35-40m in 5-6 years.
That's definitely possible. It's also quite possible that the WiiU ends up in the GC-N64 range. 3rd-party support doesn't seem like it's going to be a factor - this will be a system carried by Nintendo, and it depends if Nintendo can hit a home-run or two with some software that elevates the system beyond GC-N64 levels, or if it follows along those prior paths. If anyone is capable of delivering that breakout software, it's definitely Nintendo - they've done it numerous times spanning the history of dedicated gaming systems. But it's not a certainty by any stretch.
I'm kind of 50/50 with duckroll's suggestions. Just letting the system die after the first year or two seems premature. A big part of the problem right now is Nintendo coming to grips with HD development. It's a learning curve that they weren't prepared for, and it has pushed back their release schedule significantly. Following duckroll's suggestion, the teams would all get one HD game to work on, and then they'd be thrown right into working on an even more demanding development process. Giving them a good 4 year cycle to get their feet grounded on WiiU would seem to have some advantages before throwing them into the next gen dev cycle.
But I do agree with duckroll that there's no point going and buying 3rd-party ports and stuff. To what end? The 360/PS3 ports that they could be getting for the next year or two are going to sell infinitely better on the 360/PS3 anyway. Those franchises being released at this point already have their fan bases on those other platforms. And new games being designed for 720/PS4 will be a significant downgrade on the WiiU, to the point that the games still won't sell very well. If the WiiU had taken advantage of this first year on the market, and built up a big userbase advantage, then that strategy might have had a chance of paying off, but at this point - there's just very little to be gained from buying ports. All it would do is leave the WiiU in a situation where it's just constantly losing money.
At this point, Nintendo's best bet is to basically treat the WiiU as they did the Gamecube. Sell it at cost, so they aren't losing anything on the hardware, and make some meager profits off of the 1st-party software throughout the generation. Let the 3DS carry you through the gen, much like the GBA carried Nintendo through the GC years. They could still end up with a profitable few years that way, and then start anew with their next plan somewhere around 2016-17ish.
As an aside - the Japanese 3rd-party situation is going to be interesting to watch this coming gen. Many of them seem to be throwing in with PS4/720 as they chase the west, but the PS3/360 western market just wasn't there for them this past gen. I don't see why it would be any different moving forward into this new gen. Square Enix tried hard with all of their Eidos stuff, and even though the shipping numbers were fine, they couldn't make any money off any of the stuff. That situation is only going to get worse as the dev costs jump again next gen. Capcom had an absolutely miserable last half of the gen with their stuff in the west. The stalwarts (FF, RE, MGS) should be fine, but beyond that, this coming gen could be a real mess for Japanese pubs if they make a real push for western success.