Brawl Characters they should add:
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Yoshi
Boo/King Boo
Toad
Toadette
Walluigi
ect.
Don't keep:
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Jigglipuff
Dr. Mario
Pichu
Well, Yoshi's semi-confirmed, so you've got him. Boo/King Boo, Toadette, and Waluigi are a "no" as playable, but a "maybe" as Assist Trophies. Toad is... hmm... that's tricky. Toad's got a coinflip. He's incredibly popular and Smash is known for making movesets out of the blue for characters (they did it for Fox and C. Falcon in the very first SSB.), but the question about the moveset is what has me doubtful. I really think Toad's chances rest on a coinflip, but it's a bit more weighted on the "no" side.
As for the "don't keep"s, Pichu and Doc are as good as gone. Jigglypuff, not so much. She's a long-time veteran for Smash, but sometimes I question her return to Brawl; I'm pretty sure that she'll return, though. Roy and Young Link will be removed before her though, and maybe (but doubtfully) Game & Watch.
For some constructive criticism, I would add some reasonings to your list. Just listing your characters will get this thread deleted. Your characters are your clients, now be a lawyer for them!
In addition, expand your horizons! There's other franchises besides Mario, you know. Check out some of the major F-Zero pilots (Black Shadow, etc.), Starfox characters (Krystal, Wolf, etc.), or the Donkey Kong crew. Surf the Nintendo series and try to find characters that really appeal to you.