PS4 has many more games coming out this year than the Wii U and already has a big lead. If MK8 wasn't enough to boost Wii U sales above PS4 sales for even one week, you can be sure its not gonna happen this year.

Also WD wasn't even a PS4 exclusive while MK8 is probably the biggest exclusive that will ever come to the Wii U.

Nintendo has already gotten the hang of HD gaming, that's why they have the absolute best looking games on any console right now. Running as 720 and 60 fps makes a game look better than 1080p and 30 fps. They also don't need to churn out subpar garbage either, they're doing a good job of building a solid library.
It only took a few good games to turn their fortunes around with the Game Boy, DS, and 3DS. You don't think MK8, Bayonetta, 2 types of Zelda games, Metroid, and possibly the biggest new JRPG constitutes a few good games?

As for the best lineup, lets compare 2014 and then a little of 2015.

2014: Bayonetta 2, X, Hyrule Warriors, and Smash.

That's a good spread. One killer app franchise, one  very hyped JRPG (possibly the first system mover for the Japanese market), the first new Zelda related game in a while, and a third party exclusive that has a cult following.

2015: Zelda U, Retro's Metroid, possibly a new IP from Miyamoto(?)

So Zelda U has been a big thing people have been clamoring for, and Metroid is believed to be back in Retro's hands, and a new Nintendo IP would adress a major complaint everyone has about Nintendo not creating new franchises.

What's more, the timing of these titles couldn't be more perfect, being in the wake Mario Kart 8's elevated sales and allieviation of the doom cloud right before E3. Everyone knows that all eyes are on Nintendo and short of Microsoft buying Nintendo nothing can steal the show from them. Nintendo will either have an amazing show or pull an Xbone and embarass themselves. I believe they'll deliver because if they don't, Nintendo is dead, period.

So tell me, which system currently has a lineup for 2014 that stacks up that well, and what is that lineup?

As for third parties, they will go anywhere and everywhere there is money to be made, that includes the Wii U if it proves it can maintain sales. Not every new game is some sort of graphical powerhouse that's far too advanced for Wii U to handle. It's the first volley after release, yes most games are going to be in a graphical dick waving contest and try to focus on power and realism.Once more stylized games begin to come out the Wii U hardware will be less of a hindrance to third party releases.

This is what we call cowardly now? Ok. 

you forgot to mentione a couple of games coming out this year for nintendo, 1) sonic: might not be a great exclusive that is as hyped as the other, but sonic has a fan base and they usually boost a bit of nintendo sales. 2) skylanders: might not be a exclusive but it moves better on nintendo systems and now with the nfc gamepad it will be almost focused on wii u, and the skylanders fanbase is quite big.  might not be the best games but are still 2 more games that will boost sales for the wiiu while more drought hits the other systems.