Here's the thing. Most Nintendo characters that people en masse identify have already joined Smash Bros. Mario, Luigi, Peach, Bowser, Donkey Kong, Diddy Kong, Yoshi, Wario, Link, Zelda, Ganondorf, Samus, Pikachu, Kirby, Fox. Those same people don't know who the Ice Climbers are, who Pit is, or who Ness and Lucas are. They certainly don't know what a Game & Watch is. With SSB4, we won't be seeing the addition of any truly main characters. Sure, highly known supporting characters like Ridley, but it seems we're entering an age where a focus on cross-referencing is taking charge, an age where convergent properties and customization thereof are becoming a norm (and not just in-house stuff). Third party characters would draw more customers than a new Fire Emblem lord, a new Pokémon, another retro character the general public doesn't know, a dead crocodile villain, a girl monkey, a blue fox chick, a starfish, a guy on a bike, a samurai racer, etcetera.
But they won't totally abandon that. Of course we're going to get some new Nintendo characters, but what was on the back of Brawl's box? Oh some pictures of Brawl, yeah well how about SONIC AND SNAKE JOIN THE BRAWL!!!!!!! That's what sold the game to a lot of people. I followed the Dojo every single day, but that one October morning when I woke at 6 in the AM and loaded up the site an-BWAAHH SONIC??? THEY ADDED SONIC??? I don't even care about Sonic, but it blew my mind. Sure, we already knew Snake was gonna be in it, but Sonic came as a huge surprise. It made perfect sense, but it didn't seem like it would ever happen. Everyone I told that day had their minds equally blown. It was like this big deal or something.
So what I'm trying to get at here, is that 3rd Party characters are gonna draw bigger crowds than your favorite forgotten Nintendo characters (they haven't been included yet for a raisin). Seeing as how Ninty is already outsourcing SUPER SMASH BROS. to an out-of-house company probably speaks for their approach to the series at this point. How will you win people over to the Wii U? I remember reading some interview with someone (I don't remember, maybe you did too otherwise you're just gonna have to trust me) where it was stated (and I'm paraphrasing)
Super Smash Bros. 4 is going to be the selling point of the Wii U.
How you gonna sell a console with
this? Or how about
this? You don't. You sell it with
MEGA MAN.
PAC-MAN.
BOMBERMAN.
PETER PAN (oh wait they already have Link). Crying blue fox chick, schizophrenic crocodile king, or
. Think about it. What characters are as big as Mario, Donkey Kong, Link, Samus, Pikachu, and Kirby? Well, not many other Nintendo characters. But third parties, sure! Some insane universe where Mario, DK, Link, Samus, Pikachu and Kirby could fight Pac-Man, Mega Man, Crash Bandicoot, a Chocobo, Boba Fett, and Batman would be a pretty cool thing. We can't imagine it taking place in our own world because copyrights and companies and corporations and creative control and crucifixions exist. But what if?
Nintendo can't achieve
that 'what if', but they might be able to score some big name characters from other companies.
What if?
Edit: Oh, and if you want to really crush the competition (playstationallstarsbattleroyale) you nab 3rd party characters to better promote your game. It's a race to consume all!