Let's actually leave the ambiguous "Next-Gen" phrase right here at the door.  No need for it.  Now, moving on.

The better question is what does the Wii U bring to gaming that wasn't there before?

A Touch-Screen controller.  Ok but that's existed, e.g. on the DS/3DS.

A detached touch-screen controller.  A bit better.

But what does a detached, 2nd touch-enabled screen controller, let you do that you couldn't before, for gaming? 

Online Multi-player, nothing really.  Local multi-player - this pesky "asymmetric gameplay" term.  Yes.  No symmetry of experience.  Two or more people having distinctly different experiences in the same game at the same time.   The Wii U brings something new and great to local multi-player.

Single-player.   What does a detached 2nd screen controller with advanced motion-control, NFC, built in speakers, and a front-facing camera make possible here?  I don't pretend to be complete, but that's not the point, and here are some main ones:

1) Distinct Sound.  Now the controller can immerse you in the game with sound. Possibilities are surround sound music, channel 1 T.V., channel 2 controller, voices speaking to you through the controller only, atmospheric/setting sounds playing through the controller only.

2) Touch-Screen Motion-Control.  Now you can tilt, turn, twist, & shake the controller while viewing & touching the 2nd-Screen.  This new combination may let you e.g., turn the controller into a virtual car steering wheel, or fling motion controlled ninja stars.  Many possibilities.

3) General Immersion.  The detachment and physical distance of the 2nd touchscreen, can create a sense of immersion and reality for a game that is not possible for a console with connected screens.  For example the action on the T.V. can continue while the gamer must complete a task on the 2nd Screen.

4) 360 Degree Window.  Now the gamer can look through the 2nd Detached Touch-Screen as if a window to another world, the gaming world, or an augmented view of his home.  This isn't a product of the detached 2nd-Screen, connected-screens can do this in theory. But it is an addition to gaming the Wii U brings, to see a Yoshi pop up behind your couch or a Zelda fairy flying around your ceiling, to be in the gun-turret of the Millenium Falcon, or for real-world applications like Google Maps, and the upcoming Panorama View.

The above of course applies to multi-player.

How do we market the Wii U? How do I do Nintendo's job for them?  We market what the Wii U brings to gaming.

Multi-Player:  

1) Local Asymmetric Gameplay

The Commercial: A montage of real Nintendo fans & gamers playing together Asymmetrically, illustrating the laughter, fun, intensity, collaboration.  Don't use actors.  Use real people.  That's what strikes people.  Their reactions will give you all the footage you need.

Single-Player:
2) Distinct GamePad Sound.
The Commercial: Personify the GamePad. Show it talking to you.  Give it a life of its own. Turn it into Kitt from Knight Rider.  Show it creating sound for you that immerses you into the gaming world.  Give it a voice.

3) 360 Window.
The Commercial:  Show the GamePad holder again in a montage.  Put him in the gun-turret of a fighter plane shooting down enemy bogies all around. Show him using the Panorama game.  Show him viewing his own house with augmented reality.  Show him scanning the environment of the game-world.  A montage.

4) Immersive Life-Like Feeling.

The Commercial:  Show the gamer for example, playing Zombi U in his living-room.  Now show him reaching into his GamePad backpack and suddenly he's actually in the world, Zombies all around him.  Show the tension, illustrate the fear.  Show him grabbing the item and successfully warding off the attackers. Then cut back to the living room, as if it were all a dream.  It doesn't even really matter if it's a game that actually exists yet.  The point is to sell the console.  The point is sell its possibility and get what its about across.

5) Touch-Screen Motion Control.
The Commercial: Show the Touch-Screen displaying the image of a Steering Wheel. Show the gamer steering his racer with the GamePad. Show the flinging Ninja Stars with motion aiming.  Show the gamer tilting, shaking, turning & twisting his gamepad while using the touch-screen.

It seems to me that Immersion is the Wii U's big potential.  That's its hook.  Immersion to me, appears to be for the Wii U what Motion Control was to the Wii.  

If I were a Developer, I'd focus hard on designing around the above 5 points.  And if the game doesn't call for any of them, don't force it.

If I'm Nintendo, I'm selling you the above.  They are all easily & instantly graspable through imagery.  The marketing so far has been sub-par.  

I don't know if the marketing have been bad, as it have been mostly about games (note, that I've seen the marketing mostly on Nintendo channel on Wii). Creating hype by selling imaginary games/features/functions is kind of a plague in the industry, that's eventually only going to backfire.
Looking at how many copies and how fast the hyped blockbuster games can be found used on the used games section, people get disappointed due to high expectations.

Just a thought ...

When it comes to online multiplayer, the touch screen controller may make the Wii U the first console that is truly viable for a MMO game.

^And RTS. Now the only thing we need is games that prove it, instead of just thinking how it would work.

The Wii U is not a hard sell, developers just need to make the games. I think developers are just lazy and like to stick to what they know and not take a chance until a console has a large installed user base (I think PS4 and 720 will suffer early on because of this and the popularity of their predecessors).

But that's why I like and respect UBI Soft who has taken a chance on the Wii U from an early stage and has made an excellent first generation game in ZombieU. I now can't wait for ZombieU 2 (and Rayman Legends). I mean UBI Soft went from Killer Freaks to ZombieU in a short period of time, but some developer find it hard to simply port existing games, for example Bioshock Infinite, to the Wii U. These lazy developers suck.

So selling the Wii U to consumers is doable, but getting developers not to be lazy is an entirely different thing.

I just wrote the original post because I wanted to try and discover what exactly the heart and soul of this machine was - for gaming.

Didn't want to mention TVii, or Miiverse, or playing console games in bed, or remote control. Just what the new gaming dynamics/possibilities are. If I was wrong, well I think I came decently close at least.

My opinion is the Wii U's grand possibility for Single-Player, is Immersion. For Multi-Player it's Asym.  That's as simple as I can break this console down.  And I think both of those new creative boundaries offer ample exploration and potentially mind-blowing new possibilities for games.

I hear all the time that "Dev's are lazy." I don't know if I agree but that really doesn't matter. Let's assume they are lazy. Well - that's big trouble for the Wii U. The ease of the dev kits or the hardware architecture don't really matter compared to the extra time, thought, and creative design effort to make 2-Screen Immersive/Asym games - that push the creative boundaries.  "Lazy Dev's" won't bother with that because yeah it sounds cool, but it's so much more work, and it's not the paradigm of other machines.

the problem is not the quality of the ads but the timing
they were launched so fucking late

That's one hell of an advertorial. You should work for Nintendo. Seriously, the way you described everything seems like it would be in the back of the console box....it ALMOST made me buy one.

Hey thanks.

There's a theory floating around that Nintendo's purposefully held back the Ad's, waiting until they're needed to move inventory.