Shane ss1: DBZ is a manga, not a video game franchise. There are video games of the manga, but it doesn't qualify them as video game characters. Sakurai only wanted video game characters, and odds are that would continue.
As for Peach, she's one of the most popular Nintendo characters and a well known character to represent the Mario franchise. Even if her moveset's not as good as some others (though I'd say she's improved from Melee), it's rather clear why she's here.
And as good as Dr. Mario and Roy were, clones are clones. Roy was only there for advertising anyway.
nintendo dude: Shadow Moses was available from the start. One of the methods for unlocking Snake was by playing 15 games on Shadow Moses.
To agree with other people that have said this, the next Smash Bros should have some new characters (I can still think of some Nintendo characters that I'm surprised aren't playable), an improved online service and some DLC. The story mode was ok, but could do with some improvement. I'd also like to see Board the Platforms and Race to the Finish return for the Stadium section of the game.
By ozzo
Mission debriefing:
Now available