Sorry I've been rather inactive, I have other wikis.
Now I will post my top 10.
I think King K Rool should be in there (and not crappy Ridley cause he's too freakin' big) because we need moe villains fo'. He could have a moveset from like Donkey Kong Country 2 or 3. His Final Smash would be using cannonballs.
WE NEED BOWSER JR! Many people think he saw him AS A ROCK in the Mega Man trailer. His Final Smash? That giant thing from Mario Party 9.
Next up: Pac-Man. No big secret that Namco is helping and Pac-Man is Namco, so perfect. His Final Smash? To be honest, IDK. Maybe a transformation to Paczilla? (If you watch the Pac-Man reboot, you know what I mean).
Ryu from Street Fighter. He's perfect, Street Fighter is a fighting game. His Final Smash? IDK :P
Galacta Knight from Kirby yo. He'd be perfect, but also a Meta Knight clone (I think it would be simple) Final Smash: Triple Sword Slash.
We need Zoroark (hands down). So basically a Lucario clone, but not the Down Special. Final Smash: Ultimate Illusion.
Shulk from whats-it-called. 'Nuff said.
Paper Mario needs to come. Basically a Mario clone like Dr. Mario, but with paper thingies. Final Smash: Scissors.
Shadow the Hegdehog. He is a villain fo' freakin sake. Final Smash: Super Shadow.
And now...the moment you've all been waiting for, Number 1
We all miss Mewtwo, it needs to come back. Final Smash: Mega Mewtwo Y.