Yet they are still using dated characters who have a very limited appeal, which is the issue in selling SSB to a large audience, whereas Halo doesn't have that issue. I'm not saying they aren't good players, just the game they are playing isn't generally seen as core due to appearances. 

Dude, if people really cared about gameplay, the CoD series would have died after number 5. 

I'm not sure you can say SSB has trouble selling to a wide audience when its latest game has sold on par to the highest selling Halo game, especially since you're claiming Halo also sells to a wide audience.

7 million isn't "limited appeal," and it is a "large audience." It's actually a bigger audience than Halo: Comat Evolved, and I don't think you'd argue that has "limited appeal" or that it doesn't have a "large audience."

And appearances don't define what is core/casual; they're gameplay styles, and while Melee, like most highly successful games (incluidng Halo) straddles both, its core side skews very, very core.

People still buy COD for the gameplay, even if people like you and me might find it awful since #5. They've grown to like its mass-produced, safe, and predictable sameness, it's like the McDonalds of gaming.

Then this means that the Nintendo core userbase have grown or those franchises get the mass appeal which leds to believe that once the next installments hit the console the sales could improve.

Install bases matter little in this case. The appeal of the games drive hardware adoption. Install base only helps games that are too weak to actually sell hardware

I'm guessing people who aren't sticking around for another installment

NSMB Wii 27m -> NSMB U 2m

Seriously though, if the next best selling game after Kart couldn't get the Wii U off the ground, how can any other Nintendo franchise guarantee sales? Does this look like mass appeal to you?

I come to this discussion because I'm interested in supporting my console of choice and the company it represents. I do not feel it is either logical or necessary to bash WiiU to achieve a point. I am a HUGE Nintendo fan no doubt about it but I LOVE my experience with my PS3. What I find vulgar is people's inability to see what Nintendo are doing or at least trying to do. There are some ugly decisions made regarding this console that I openly acknowledge but there are things they are trying to do that are wonderful. NintendoLand is awesome; a brilliant game given no chance of exposure which is Nintenso's fault. However hating on it and saying words is also counter intuitive. Nintendo's excellence comes from the fact that their games sell like hot cakes regardless of install base whilst other company's cannot match that success regardless of massive console sales. I would not and will not bash other companies and I kindly ask that the sane is not done to a console manufacturer that create experiences memorable to those who haven't even bought a console. Mario is timeless; GTA is not. My mother who has no compulsion toward video games has played Mario Party with me and loved it. Just cut some slack.

Actually it made sense. Lets have a look at electronics in general. Design is a huge factor when it comes to success. While PS2 wasn't that pretty it looked not like a toy. Now the Gamecube looked totally like a toy. Nintendo learned and all their stuff looks not like a kiddy toy now.

I think it was a huge factor in its demise. No DVD and Kiddy Design. People want mature looking stuff even if they run Mario on it.

Wii U is priced above the market NSMBU is aimed at, and even if it wasn't, even casuals need more than one appealing game before they drop hundreds of dollars on a console. Kart will help because it will help build such a library.

You realize NSMB Wii launched when the Wii had a huge install base and it's been selling since 2009, while NSMBU was release on the Wii U's launch day (meaning no install base) and it's been selling for only 4 months. There's no point in comparing those 2 games, at least not for now.