Warning wall of text coming!
Don't worry I type fast. I can do this in 10 minutes or less, and I enjoy it too so it is not a waste of my time or resources.
I had some characters who I thought deserved it.
Takamaru: I think even though he is a Japan only character he deserved to be in because he is a retro character and he is very different than any other swordsmen on the roster. He fights with a katana in a distinctly Japanese samurai style fighting that is different than the European style seen by Marth and Ike and Link and the like. I think Japanese people who would have played Brawl with him in would like him because they could relate to him more than they could white-western European patterened people such as the other swordsmen in Brawl.
Sukapon: Another good retro character. I like him because he is a robot and they don't have to go through the avenue of 3rd party to get a robot like Megaman, and he won't be a projectile spammer like Ray 01 or Ray Mk2 would be. He still looks a lot cooler than someone like Marina Liteyears too. This robot Sakurai said he would have put him in if only he wasn't so hard to program in the game but he'd be the most unique character being a bunch of pink balls floating around fast and hitting you. Sukapon's game Joy Mech Fight is the prototype if you will of the Smash series, it's Nintendo's first fighting game.
Krystal: No, I am not a furry but I still think Brawl lacks in the amount of non-human realistic characters and Krystal would be a cat girl who fits in. I am sure some boys here would like her because they think she is sexy, but I don't think she should be in for the sex factor but because she would a very unique Star Fox character and be an animal character, who could use a staff fast and long range like Marth's attacks. If they keep away a reflector and a landmaster she could be very unique.
Paula: This one I think many people think would be the most unexpected character, similar to ROB. I think Paula deserves in more than Lip does even though Lip is much older, because Lip's stick is already there. The MOTHER series deserves more than 2 reps, and I think it should go to her over Claus because Claus died at the end of Mother 3 and the lightsabre he has wouldn't fit in Brawl because they also already have beam swords. She would also fit in with Ness and Lucas more because they are more or less the same size as each other, and Kumatora I don't think would work as well because she is older and taller than Lucas or Ness, making her a bigger target who wouldn't fit in with her smaller counterparts unless she leans over low to the ground like Wolf does although Wolf is bigger than Fox. Paula's personality would be good as she would be a highly religious/spiritual person who I think would be good as a contast to the rather secular-like nature of the rest of the characters, and her final smash would be pray which would cause random chaotic things to happen.
Mona: Mona I feel deserves to be in as a Warioware rep because Mona is Wario's most important employee, and she offers a unique moveset. She worked as a rockstar, a cheerleader, a pizza delivery girl, and a ice cream seller person. A very wacky character, she could use a variety of moves that involve her cheerleading baton which she would hit people with similar to how Pit uses his double sword. She could also call upon her pet pig, elephant, and monkey with a tech-visor on to help, and also wack people with her guitar as well. She could be very wacky like Mr. Game and Watch and have multihitting attacks with her cheerleading baton that are similar to how Pit attacks. She also would double as a female AND a villain character because in her games, she uses her animal friends to crash police cars causing the deaths of potentially dozens of policemen who chase her as she speeds to get to work on time. She would be a highly reckless, sometimes irresponsible, and potentially evil character who would work well with Wario or even betray him (or the otherway around) if she had the chance.
Megaman: He would make a good third party character. I'd like him though in his classic form. Not much needs to be said about him, just that many people like him is already more then can be said than words.
Micaiah: I like Micaiah more than Lyn or another FE character because she doesn't use a sword, and Takamaru would be using a Katana so that means that Lyn would be out. Micaiah would break the stereotype that Fire Emblem is always about blue-haired swordsmen, and she uses light magic. If done right, she doesn't need to be a zelda clone but perhaps my thoughts are that they could give her health-stealing moves to repersent in Brawl that she was a good healer character in Fire Emblem. Also, no one else in Brawl has silver hair I think. So she'd be unique in that regard.
Muddy Mole: Like Paula, I expect people to raise their eyebrows at this guy. Sakurai said he was so interesting, he would already be in the roster! Muddy Mole is a mole who tries to save his children from an evil farmer named Jinbe, but what I like about his that he is an animal so we don't have too many human characters and he can bury underground. He'd be small and can move without fear of getting hurt under the stage. Another cool think I like about him is he uses claws, so he'll stratch you really bad too and I'd expect him to be very fast. So there'd be mostly four methods of attack in Brawl: Fists/kick, swords, claws, and staff weapons.
Ridley: Ok, I have to jump on the bandwagon but I thought he'd be a good idea too. He can fly, and shoots plasma out of his mouth. His tail is also a good weapon, and he is a non-human character although not cartoonish like Muddy Mole or Kirby or Pikachu or something. If they resized Bowser, they could have resized Ridley and the Metriod series wouldn't have got the shaft.
Geno: I must agree I am not a 'rabid' Geno fan but I would like it if he did come. While owned by Square-Enix, he would have been very unique especially for a game that sold about 1.4 million copies (correct me if I am wrong), even more than MOTHER 3 sold in Japan (only about 300,000 copies). A talking doll is a very unique thing, he is not living organic matter but rather made of wood yet very powerful and humble. I felt he deserved his place in Brawl.
Pious Augustus: This will make people even more wierded out than Muddy Mole or Paula... I think Pious Augustus would be good in Brawl because Nintendo's horror genre is horribly under represented. While I like Alexandra Roivas and the voice behind her (Jennifer Hale), her voice is already doing ZSS and ZSS also looks too much like Alexandra too. Pious Augustus though is a Roman soldier who uses occult evil magic and is armed with a staff made of a man's bones. He could also use his gladius, and then he'd be like Gandalf from LOTR using both a sword and a staff dual-wielding! Like an evil version of Gandalf, except he'd be evil and a Liche who'd look very scary. No one else on the roster would look as scary as this guy, with his skull face yet he'd have good voice acting that is for sure. Maybe in SSE, they could have him and ZSS fight since ZSS is played by the same voice actress as Alexandra was.
Isaac: Ok guys. Another sword user, but he'd be different in that he uses more magic than sword. His magic would be different than anyone elses, as he summons djniis(sp?) and vines and stuff, not the common fire ball that Zelda/Mario/Ness/Lucas does all the time. Oh, and his hairdo would remind people of Sora since Sora was liked so much, so when you play Isaac you would just pretend you're Sora then you're good.
King K Rool: Donkey Kong could use another rep, and he's good he is an animal character who is a heavy weight. We need more heavy weights, like Bowser and he'd be a good choice. He could use a gun, the closest thing you could get to a real gun but it'd shoot out a slow bullet with spikes on it so Sakruai wouldn't consider it a banned item. No, it won't cause Columbine shootings if kids see K Rool with a musket gun called a Blunderbuss in the game.
DeMille: A rabit character, I think he'd fit. He is a 'cute, small' bunny rabit who is 8 years old from Tomato Adventure and would be needed to balance out all the more serious looking character suggestions as far as cute characters go. All his attacks would be even wackier than Mona's. He'd cause a train to come and smash into you, and use a hover board.
When I first saw him in 2001, I thought he was a Castlvania character because of the music that played when you fight him. 
yscho: 