Now that I've played Golden Sun, I think Isaac would be cool.

Mega Man, no question

Shadow the hedgehog would be awesome

Isaac from Golden Sun. Seriously, he should have been playable in Brawl. Also, Lyndis from Fire Emblem would be nice.
Furthermore, I want Roy back! He was my main in Melee.

Oh, Mike Jones and Little Mac would be nice too.

Mike Jones. StarTropics.

Grey Fox and Saki should have been playable characters instead of trophies. However, who I would really want to see would be Travis Touchdown. It would be fun to slash opponents with his beam katana and perform wrestling moves on them. His special should be that he calls out Glastonbury and has it perform it's London Missile attack.

Sakurai

Oscar from the DSiware games

Eh, they can put any character they want into the next Super Smash Bros. game, I'm not gonna care - I probably won't play it, anyways. I've moved on from the SSB games to bigger and better things. Real fighters are where it's at! ...But, if they added some cool Non-Nintendo character, like, say, Mega Man, or Ryu, or Tails, I might be willing to change my tone.

Any more characters?

Here's who I want:

• Crono (Chrono Trigger)
• Magus (Chrono Trigger)
• General Zelgius/The Black Knight (Fire Emblem: PoR & RD)
• Simon Belmont (Castlevania series)
• Alucard (Castlevania series)
• Mega Man (Mega Man)
• Proto Man (Mega Man)
• Zero (Mega Man X)
• Poo (Earthbound)

Also, I feel like they need to add another Metroid character, whether it's Dark Samus or someone generic like a space pirate. Some Final Fantasy characters would be good, too.

No more than a few third-party characters.

More characters from lesser known first and second party games and more villains.

Specifically, Isaac, Ivan, Vaati, Zant, Waluigi, etc..

Earthworm Jim:
B- Blaster Charge
B Side- Head Whip
B Up- Head Propeller
B Down- Fishbowl
Final Smash- Space Vortex

Lord Hector and Lady Lyndis from Fire Emblem.

Easily both more fun than the two FE characters they have now.

Saki(S&P) and Flint (mother)

The characters from The Legendary Starfy, and the characters from Chrono Trigger.

Square will just say no again

Q-bert with the ability to combust his opponents when he jumps on them, suck and blow stuff(I guess...), and for the final smash, "The Demonic Swear" in which he shouts out the forbidden word so despicable that all the opponents in range would have their heads explode!

I would be upset if they made Waluigi playable. The only reason he even exists is so Wario would have a partner in the spin-offs. He hasn't appeared in a single mainstream Mario game to date (unless you're including SSBB).

Batman from Arkham Asylum
Ezio from Assassin's Creed II
Lightning from Final Fantasy XIII
Rookie from Halo 3 ODST

...and I doubt he would make it in there, but I also want Mario.