The drawing was made by Masahiro Sakurai, the creator of the series. If you don't trust that drawing, don't worry, Marth is the main character from the franchise, and he's the protagonist of two recent games, an iconic character from 90's RPG titles, and very popular around the world. He's going to be in the next Smash Bros. for sure (he was even going to appear in the N64 smash bros!).
I know about the whiteboard drawing and about Marth's background.
Yes the whiteboard was drawn by Sakurai but it does not mean anything about character returns and such. It's also true that Sakurai does not want to add to many new characters or focus the game on characters due to wanting to keep balance between characters. So the roster we see in Brawl may be the same roster we see in this next game.
And also true while Marth is the face of Fire Emblem it may also mean he may have a good chance of returning.
Guess I am just paranoid...I've been attached to Marth for a very long time...I don't want him going and being forgotten about again.
I didn't know he was supposed to appear in the N64 Smash...I knew Pit was but Jigglypuff took his spot. Due to Pokemon at the time was far more popular than kid Icarus.
I also have this issue about female characters taking the spots of male characters, no I am not sexist and say female characters should not be in video games. I just...do not take interest in them as much as others do.
It's like how people want krystal to take Falco's place....no...Falco deserves his spot.
Our beloved prince will return for sure. Many people complain about having just a few female characters in the smash bros. titles... but that's Nintendo's fault, not Smash bros. fault. However I'm sure we'll be seeing Palutena in the next title as well, so that sorta solves the problem. About the star fox characters I think Fox and Wolf will return (¿clones? ¿seriously? they only have similar final smashes!), Krystal won't be added and Falco... we'll see.