But what if it's NOT that game and this is something mindblowingly new and awesome???

But, yeah, it probably is that game.

I wonder... is this a case of announced, like with release information? Or like Pikmin 3 announced?
I'll take a quick 2d platformer at launch with a couple of years to refine an experience to rival Galaxy, thank you!

I’m not saying this new game isn’t NSMBM, but if it is a side-scroller, I feel it will be much different than what was shown at E3.  I’m pretty sure Takashi Tezuka already said in the SM3DL Iwata Asks interview that their next game may be influenced by the work on SM3DL (how that’ll work, no one knows). Also, why didn’t they show the demo at CES? With how secretive Nintendo is, do you think it’s logical to show a new Mario game, then deny the fact that it will eventually become a game, when in fact that is exact game you’ll get? I plan to buy Wii U, but if Nintendo tries to offer me the same experience I paid for on Wii in 2009, it’ll kind of feel like a kick to the balls. If the extent of this new controller is that you can play a game solely on it, and Nintendo themselves choose not to expand that, doesn’t that send an antithetical message? And, Neal, according to your article on Nintendo’s developers that NWR had some weeks ago; what new games have Takao Shimizu and Tokyo EAD group 1 been working on since Galaxy in 2007? I think there is a very good chance this game will be new 3D platformer. No matter what happens, I’m preparing to be impressed in six weeks. This is Nintendo’s golden ticket to prove any Nintendo nay-sayer wrong, and they know it.

You know, house3136, I hope you're right. I'd much prefer a mind-blowing reveal of a new Super Mario Galaxy-esque game (and good on you for citing my Nintendo dev article. I'm glad people liked that.).

And I'm not being fatalist/pessimistic when I say that I think we're just going to see New Super Mario Bros. Mii with some special sauce we don't know about (3DS to Wii U co-op?). I'd still play and likely enjoy that game.

And they didn't show the demo at CES because the Wii U blowout is being saved for E3 2012. There's no conspiracy theory behind that; it's just how Nintendo works right now.

And LudicrousDave, it wasn't formally announced (I guess it was just as announced as Pikmin 3, technically sort of), but it was shown off during the Wii U presentation during the E3 presser, and it was playable on the show floor. As I said, Nintendo's official line for the E3 2011 demos were that they were "experiences" and not representative of full games. However, when they did that stuff with Wii, most of those "experiences" were congealed together for Wii Sports/Wii Play/etc.

Hopefully this game is the do or die moment for multiple tablets.

I absolutely believe there will be a somewhat strict 2D side-scrolling Mario Bros. title and a 3D Mario platformer on Wii U; it would be ridiculous if Nintendo didn’t have them. It is somewhat confusing to imagine how a 2D, multiplayer platformer could utilize the controller beyond direct screen transmission. Honestly, I kept thinking that’s all we would see, at least this year, was a New Super Mario Bros. of some kind. I didn’t seriously consider a new 3D Mario until I read about Tokyo EAD group 1 in the developers article, so thanks again. Except, with a new technological platform, I can see an evolution in these series to show something fresh; it seems a lot of times Mario, and other Nintendo franchises, get unfairly accused of being rehashes. Think SM64, Sunshine, Galaxy, and it gets people anxious about what’s next, positive or negative. Regardless of release dates given at E3, I still think we will see a multitude of games to be excited about. Since Iwata already announced it, most likely the new 2D Mario 3DS game will be out for this holiday, or spring 2013; I’m expecting a Zelda 3DS release within the same period. Also, the PAX videos were great.

If it's just "well you can switch from the TV to the tablet" how is that really anything?  That doesn't affect the gameplay in any way.  You could put that feature into SMB1 and it would still be the exact same game.  Hell that feature seems more like unique functionality of the console itself which should be available for ANY game that does not explicitly require both the TV and tablet screen to be used at the same time.  Did Nintendo promote the Wavebird as some amazing feature of Super Mario Sunshine?  No, because while playing with a wireless controller is pretty cool it has nothing to do with the specific game being played.  It was a console feature and if Nintendo has stupidly designed is so that games HAD to specifically be programmed for it it would have been a joke.

To really demonstrate something worthwhile there has to be some interaction with both the TV and tablet displays being used together.  Of course Nintendo had this feature on the Gamecube and the DS and didn't really come up with anything particularly impressive with it so I am incredibly skeptical of them suddenly having a bunch of awesome ideas that for whatever reason they either didn't use years ago or they only just thought of now.

As was mentioned in the Wii U rumors thread, Nintendo registered supermario4.com back in 2007, so it's not "recently registered".

I hope this is a 3D Mario, not NSMBM (not that I hate the NSMB games).

I think it will be something different from the Super Mario Mii game, at least I hope it is something different. Can't say I'm horrible excited for a Mario game that has been Miized, not to mention the NSMB style hasn't impressed me that much.

Called it: http://www.nintendoworldreport.com/news/29838