Here is an excerpt from some Smash Bros. DS design document I made in 2004. It deals specifically with characters (the excerpt), lol at what I wrote about Meta Knight back then:
The Roster
My idea for Super Smash Bros. DS is for it to have 14 characters in it. The reason why there is 14 characters is that I feel that a lot of new characters should be added to whenever the next Smash Bros. is made for Nintendo’s future home console. There should be only a few great newcomers added to a portable Smash Bros., it should not be the true successor to Melee (this would be more of how Mario Kart: Super Circuit was more of an analogue to Super Mario Kart than Mario Kart 64). A true and proper Smash Bros. 3, would have the entire cast from Melee, the new characters from Smash DS, as well as at least 14 new characters to the franchise.
However, despite Smash Bros. DS’s roster having roughly the same size as the original Smash Bros. for the Nintendo 64, over 1/3 of the roster will be made of new characters to the Smash Bros. series, not having been playable in Super Smash Bros. Melee.
The roster will consist of the following:
Mario
Bowser
Link
Ganondorf
Pikachu
Mewtwo
Samus
Ridley (NEW)
Kirby
Meta Knight (NEW)
Fox
Wolf (NEW)
Toad (NEW)
Wario (NEW)
Fourteen playable characters total.
As can be seen overall theme to this game will be rivalry. Half of the roster will be made up of heroes, while the other half will be of villains or antagonists. The starting roster will consist of the heroes, which are all characters that were playable in Super Smash Bros. Melee, with the exception of Toad. The villains will all be hidden characters, all but three of which, are characters entirely new to the Smash Bros. series.
New Character Reasoning
Wario, Ridley, Meta Knight, and Wolf are all extremely popular Nintendo characters. According to polls on the message boards on a multitude of different video game sites, most of the people who answered them requested that these four characters be made playable in the next Super Smash Bros. installment.
Wario:
Wario has a lot of games under his (bulging) belt. He has not only one, but TWO series (Wario Land and WarioWare). His popularity has soared to great heights thanks to the WarioWare series.
Ridley:
Since the revival of the Metroid series, Ridley’s popularity has quintupled. He has starred in five out of six games in the Metroid series. Both the developers and fans of the Metroid series consider Ridley to be Samus’s true arch-nemesis. His role in the series is leader of the Space Pirates, the main antagonist force of the series. A lot of people wanted Ridley for Melee, and even more people want Ridley playable NOW.
Meta Knight:
Meta Knight has been somewhat of a side character for the Kirby series, being a knightly rival to Kirby and antagonistic in many of his appearances. His playable appearances in Nightmare in Dream Land and Kirby’s Air Ride, has made his popularity surpass that of King Dedede, making him the favorite for a new Kirby character in Smash Bros. However, there are some Smash Bros. fans that are concerned with putting Meta Knight in because he may become a “cheap” character. For example, Meta Knight as a character has fast speed, good jumping, and a sword. They think that Meta Knight must be properly balanced before being added as a playable character.
Wolf:
A lot of people were expecting Wolf for Super Smash Bros. Melee due to his appearance in the Melee intro (the same was true for Ridley and Samurai Goroh). Instead, Falco got in. However, despite this, there is still a hunger (or rather a howl) for Fox’s rival. However, there is a worry that Wolf would be too aesthetically similar to Fox to place in or, that Wolf would be yet another clone of Fox. However, Wolf being a… wolf, means that he would fight very ferally and ferocious unlike the more honorable and disciplined Fox McCloud.
Toad:
Toad will be a “pleasant surprise” character. For example, most people were not expecting Mr. Game & Watch to be a playable character in Super Smash Bros. Melee, but were happy to see that he had made the list. Even the original Smash Bros. added an oddity in the name of Jigglypuff, so adding a stranger, less notable new character is within the history of the Smash Bros. series. Toad also seems like the most appropriate rival for Wario. Toad had to fight Wario’s minions in the classic puzzle game Wario’s Woods for the NES and SNES (Wario’s Woods for the NES was also a playable game in Animal Crossing). Toad will also have the unique ability to run up walls like he did in Wario’s Woods.