-Ax Battler (from Golden Axe)
To be more precise, I mean from Ax Battler, an obscure Golden Axe spinoff for Game Gear, with a gameplay inspired by Zelda 2.
Why I want him? Because he's an heavy two-handed swordman, and not a JRPG guy (not a typical one at least). In the game Ax Battler, after you visit all the gyms, you learn many new moves and he gains a full moveset that works well as a starting point for Smash (and especially, that sword moveset is different than most sword movesets in Smash, allowing him to be unique despite being another sword fighter).
-Villager (from Age of Empires)
It's a generic villager, but depending on the attack, he gains traits from other units from the game. For example, he can transform into the priest and try to "convert" opponents (stun them and make them temporarily unable to hurt you), or become a knight or an archer. Like Animal Crossing's Villager, he can also build structures on the stage; he can build a tower that can shot arrows and protect you for a limited time, or build some siege weapons and slowly move them on the stage.
-Max Damage (from Carmageddon)
This is just because I want to see him fight against Cpt Falcon. Max Damage would have a mechanical arm that allows him to use several gimmicks from the game. He can use the "opponent repulsificator", summoning springs that will launch away the close enemies, or throw bombs/release mines. He has a damaged car door connected to his mechanical arm that he uses as a shield and as a weapon at the same time. (it will never happen because of the violence of the Carmageddon series, and not only for that anyway, it won't happen because it simply won't).
-Alleycat (from an old DOS game called Alleycat indeed)
It's just a cat.
Occasionally, he can summon a broom that allows him to fly (but it hurts -.-); he can leave gifts on the stage that attract and stun the opponents, and can also leave dirt on the stage to slow opponents down. His enemy, the dog, decided to cooperate with him for once, and it's summoned during his final smash.
He may or may not appear as flat and pixeled. For sure, he is completely black with no details aside of his silhouette and his eyes. Not even shadows, he's just pure black.
-Load Ran (from Twinkle Star Sprites)
Why not a magical girl too? Well, she's not the usual magical girl, she's... yes, she is, but the gameplay of her game is cool and very innovative.
Twinkle Star is an hybrid between a classic shooter/bullet hell and a competitive puzzle game like Puyo Puyo or Puzzle Bouble. You control Load Ran seen from above, and enemy formation move down through the screen (that's splitted in 2, one side for each player). When you defeat an enemy, it will explode and cause a chain effect. Doing combos will generate several fireballs that will be launched to the screen of the opponent; if the opponent manages to hit he fireballs enough or trap them into a chain explosion, they will be reflected toward you again; if you reflect them back once again, they will disappear and be converted into special attacks or even boss attacks (you summon a boss into the opponent's screen!).
Well, it's hard to explain, you should try it to understand.
In Smash, this mechanic of reflecting hits should be the main gimmick of the character; she also has a basic special attack, that's similar to Samus' charged shot, with the difference that she can build up an energy meter by dealing damage, extending the amount of charge you can give to your shot: if you charge the attack enough, you can also release special attacks and summon a boss while shooting the thing.
-Kurt Hectic (from MDK)
He's a sniper, from a crazy shi-fi series that's a parody of superheroes comics. He has a special armor with a visor that can be used as a sniper rifle, or detached from the helmet and used as an arm rifle. In the original games, he can use several gimmicks such as the smallest atomic bomb in the world, and a puppet that tricks the enemies into thinking it's him and he can move around unnoticed. He can also summon Max, a dog with 4 arms who in the first game used a dog-shaped airplane to launch bombs on the stage.
The most interesting thing of the MDK series is the setting of the first game/beginning of the second: the Minecrawlers. The Minecrawlers are huge alien machines that destroy everything they move onto. They are HUGE, they are almost as big as a real world city, and they indeed attack cities for all around the world: you must infiltrate into them and stop them from inside, by defeating the boss who's controlling them. A Minecrawler would be interesting as a stage, especially due to all the surreal environment that they have inside, and the suggestive effect of being over a colossal machine that runs over a city, seen from outside.
-Lucia (from Psychic World)
Lucia and Cecile are two sisters who work in Professor Knavik's laboratory. One day, something wrong happens, and all the creatures from the laboratory escape and cause panic. At the same time, Cecile was kidnapped by the monsters! In order to save Cecile, Dr Knavik gives Lucia an headgear called ESP Booster, that's able to enhance the psychic powers of the user. At the end they discover that Knavik is an alien in disguise and he was the bad guy all the time.
Lucia has several psychic attacks, ranging from elemental shots to teleport, fly, invincibiity and explosions. This game takes inspiration from Megaman and Metroid (mostly Megaman though).
The main gimmick of the game, that would also be part of the Smash moveset, is the ability to change power by pressing Attack+down. When you do it, you can select the wanted power by moving the cursor right or left. When you release Attack+down, the selected power will be used (that's similar to Shulk's monado arts). Like Megaman, Lucia would have projectile based smash attacks, and those attacks would have different effects depending on the selected powers. Additionally to the usual fire, water, ice and pure ESP, there is a wave shot, that won't knockback the opponent, instead it will just damage it and go through walls and obstacles. Ness and Lucas have a rival now (Mewtwo too).
P.S.: Lucia is the pink haired one, obviously.
-Dust Mite (from Re-Volt)
An RC car from a racing game. WHAT? An RC car in Smash? That's the craziest pick for sure!
The cars from Re-Volt are sentient toys, they were brought to life for some mysterious unknown reason and they just started racing randomly. They are characters, even if they don't have a face.
Dust Mite is one of the slowest cars, though it's the one of the cover of the game, so it's the most iconic.
How would a car interact with opponents and items? By using the antenna, obviously! It can grab items with the antenna, and use the electric shock to stun and grab enemies.
Re-Volt cars can also throw rockets, leave oil on the track, launch heavy bowling balls, launch water balloons, launch a beam that distorts physics, and, especially, EXPLODE. They can also jump, but only in battle mode. Smash is a battle mode, right?