Notes:

There's a widespread belief among fans of the Super Smash Bros. games, and those who like to speculate about the character roster, that Game Freak, the company behind the Pokémon series, approach Sakurai with requests and demands for which Pokémon should be playable characters. Their motives may be inspired by marketing, by popularity contests, or by high-level corporate bribery (I made that last one up). But according to Junichi Masuda and Shigeru Ohmori, Pokémon representatives are chosen just like all the others: by Sakurai himself.

Even since the very first Smash Bros., it’s been Mr. Sakurai coming to us with ideas saying, “If we put this Pokemon in this game – in Smash Bros. – we’d be able to show it off in a really cool way and do something really cool with it.” The origin comes from Mr. Sakurai. We typically go with what he wants to do because he’s really thinking of not just showing off the character in a cool way, but making sure it makes sense and works really well from a gameplay perspective. We leave it up to him.
Many of you may see this and say, "well duh," but I've seen many, many fans claim that so-and-so Pokémon will be a playable Smash character because "Game Freak wants to promote it" and "Sakurai isn't the one who chooses playable Pokémon." But now it's settled. Is this news to you, or had you assumed this was the way it is?

- See more at: http://www.gamnesia.com/news/game-freak-doesnt-choose-which-pokemon-make-it-into-smash-bros#.VD3fpvnF_w9