Nobody has talked about it yet so I thought I would. The game is pretty frikkin awesome. Not in the way you thought it would be in the trailer, but in other ways.
In the preview trailer they really try to sell you on these bonus modes, like the Ikari warriors style level, clone cherries, ect. Most of these things, in reality don't factor into gameplay all that much. The cat suit is the star of the show and it's actually quite good. Also if you were looking for a solid multiplayer experience, look elsewhere. Don't get me wrong, you CAN play up to 4 players at once and it IS quite fun, but most of the levels are really geared towards a single player experience. If you want to do any serious gaming... like collecting stars and stamps, you want to play the levels alone.
Anyway, onto the good stuff. First off the game looks amazing. Yeah it sucks that the Wii U is "underpowered" compared to the other two but considering the art style of Nintendo games I think the Wii U has more than enough oomph. The characters are perfectly rendered, no jaggies, no polys... the shadows and reflections all look perfect. In terms of a "cartoon" game this is the best I've ever seen hands down. Secondly going back to it's smb 2 roots the different characters do play completely different and certain characters work better on certain levels. Mario is kind of well-rounded, Toad runs really fast, Peach does her skirt float, and sadly, in the year of Luigi, "green Mario" is fairly useless. He can jump much higher, but his jump is really hard to control and considering the cat suit and various other power-ups let you climb/jump high anyway there isn't much point to him. Also shortly after finishing the main game Rosalina is unlocked. She actually has a spin attack available at all times, making her a fun addition.
Also stamps. Yeah it is busy work but the stamps you collect in the game are drawn in that classic smb2/smb3 style and really hit a nostalgia bone with me. You can use them to make pictures to post on miiverse. The levels are the best part of the game. Each main level is quite unique, there are zero "repeats" of concepts. This is both a good thing and a bad thing. On the one hand it means all upteen-million (hillbilly math) levels are totally unique. On the other hand it also means that interesting concepts like the level where you only see a silhouette of objects in certain sections and the ikari warriors bonus stage are only used for a single level. I don't want you to misunderstand though, there are repeats, but it's stuff like bonus levels and revisited boss battles. Also the sheer number of levels might be more than any Mario game, even Galaxy 2. It's a standard 8 world deal, 8 to 10 levels per stage but then... Think you've beaten Bowser? Nope! One more world to go. After you beat him is that the end? Nope, now the Galaxy world is unlocked. Think that's the end? Nope apparently there are two more worlds to go. Even after all of that, you still have to go back and beat every level with every character to get 100% completion.
Also to those that don't like fiddling with the camera this game is for you. While you do have the option of controlling the camera, you don't really have to. Every stage has good camera positioning with the exception of the Captain Toad bonus levels, but the whole point of those is to monkey with the camera. Motion controls are minimal. Blowing into the mic will make hidden objects shimmer and one or two levels make you blow into the mic to power gates. You can tap on characters and objects with the touch pad, but it isn't required. The controls on this game are decidedly old school and that's a good thing.
I only have two real faults with the game. Firstly the shadows on the characters aren't dark enough. This sometimes makes it difficult to figure out where you are in 3d space when jumping. Eventually you get used to it, but using the old fashioned "video game shadows" that are on the ground at all time would have helped. Also there isn't any story to speak of. I know, I know it's a Mario game what do I expect.....but we are introduced to brand new characters in this game... the little fairly princesses, but no explanation as to who they are or where they came from is given. I haven't gotten 100% completion yet, maybe they have an ending, but it's looking doubtful.
Anyway it's really fun... short in modern video game terms, but fun. Is it a system seller? Well maybe. For me I buy Nintendo consoles for the Mario games. Most people buy them for Zelda though. If you are expecting depth from this game like Zelda or even Galaxy, look elsewhere. There is a ton of content, but I've had it for what, three days? And I've beaten the main part of the game already.
If you have a Wii U pick it up. If you don't have one find somebody who does and go play it. You might be surprised.