No More Clones
Even in Brawl, they still exist. Link & Toon Link, Fox and Falco, Gannon and Capt. Falcon, Ness & Lucas....
They may not share the exact same moves or abilities, but they're still might close to one another. Creating fun, balanced fighting games with lots of characters isn't easy, but if you're in it to make money, you have to show that you can do as well as the Street Fighters, King of Fighters, the Virtua Fighters, the Guilty Gears, and the rest. The King of fighters games have managed to keep a large cast of characters feeling unique and different from one another. There's often been move set changes here and there, but you were also getting something a bit different with each new iteration of the game.
Back to Smash Bros.. Take Link and work on making him a better character. Then, you either get rid of Toon Link or change all of his attacks completely. The Zelda series shows Link using different attacks with weapon and items (Hammer, Biggeron Sword, Bombchu, Ice/Fire Rods, Candle, Special attacks, etc.), and interacting with different characters (Fairies, Epona, Goron, Cuckoos, ets..), so there shouldn't be a reason why you have two Links with the same moves.
No more cloning of special attacks
Pikachu and Sonic. Shiek and Zelda. Fox, Falco, AND Wolf. Slightly different, but mostly the same.
I say, give them something different. There are a series of games that these characters come from, why not have different moves for them all. With a larger team of developers, this'll probably come true.
Adding Characters
Like I've said, it's not easy to have a large cast and keeping them balanced, but I doubt that the next Smash Bros roster won't grow. Nintendo has a bunch of characters that have gone unused in playable form, like Krystal, Daisy, Little Mac, the cast from the Custom Robo games, Birdo, hundreds of Pokemon, Starfy, Tom Nook, the cast of Golden Sun, the protagonists from the Famicom Detective Club games, and Toad (Super Mario), and now, there's a new generation of character that could be added, like Miis, Roselina, Midna, Ashley Mizuki Robbins, Captain Rainbow, and more.
Will most gamers outside of Japan know who these characters are? No, but it shouldn't matter much. Most didn't know what Fire Emblem was, and was still okay with having Marth and Roy on the roster. Hopefully, adding unfamiliar faces will get Nintendo into thinking that some of these games shouldn't be hidden from the rest of the world. R.O.B was also unknown to the masses when it was introduced again in Smash Bros. Brawl. I don't think it'll hurt to add more unpopular characters. It just may do us some good in the end.
Third Party Characters
Will we see them again? I hope so. It was refreshing to see them, and actually got some people interested when they saw Sonic or Snake. Like Tatsunoko Vs Capcom, there shouldn't be a need to only add the most popular characters for the western world to enjoy playing as them, but in this case, it's probably better off sticking to, since the amount they'll add will be limited to only a few character slots.
You won't get the entire main cast of Sonic the Hedgehog characters, but you'll get Sonic, and maybe Tails and/or Robotnik. Mega Man would be nice, but which version should be used? Would it be the original, X, Zero, Legends, Battle Network?
Street fighter cameos would be a good one as well. We've seen Cammy out of her element of 2D fighters in Capcom's Cannon Drill, a 3d brawler/Shooter. Personally, I'd love to Rainbow Mika Nanakawa appear once more in any video game, and having her in Smash Bros. would put a goofy smile on my face.
Will Snake return, or will Konami allow another one of their characters to join? Goemon and friends from the Mystical Ninja series would really surprise me. It's a known series that have been around Nintendo consoles for many years.
There's also Castlevania which would please many gamers, but if they really want to go weird on us, they'd add a character from the Tokimeki Memorial series, with music and stages (school, park, beach, shopping center, etc.). I know, it's really japanese, but there's also a shortage of female characters. The series have plenty of girls/women to choose from.
(continued in next post...)