No New Mario Character: While I personally advocate for new Bowser Jr. and Paper Mario, I do think that other characters do out-prioritze them.
Dixie Kong: Being planned for Brawl to an extend means that Sakurai knows what she can do, and I believe it's fully possible to make her different than Diddy Kong.
King K. Rool: Had a large amount of pre-Brawl popularity and it's only increased since then. Being the most popular character internationally (every region in the world, as far as I'm aware, has him in their top five, and I think he's the only character with this feat).
No New Zelda character: Not warranted imo. I don't believe that Toon Zelda can differentiate enough from normal Zelda, and that's the only Zelda newcomer I see happening.
Takamaru: A character who's become international since Brawl, and he pretty much has a moveset made for him from his 1986 game, which is very impressive.
No Ridley: While Ridley isn't as low of a priority as a new Mario newcomer, I do feel that showing a wider variety of Nintendo franchises is a higher priority than Ridley.
No Palutena: As much as I love the character, I really am doubting her chances. Her biggest claim to fame, her popularity, may not have had a chance to grow before the roster was finalized, and Sakurai is modest with his own creations, which includes his creation of the revamped Palutena.
Karate Joe: Rhythm Heaven is a fairly large franchise in Japan that's existed since the Gameboy. His moves from the games within Rhythm Heaven pretty much write him a moveset ala Wii Fit Trainer.
Starfy: Being a "Fighter Related" trophy in Brawl makes me think he was planned for the game, but was taken out because Sakurai didn't think Starfy would be a character people wanted to play as. Wii Fit Trainer changes things once again, which makes Starfy rather likely in my opinion. Starfy is also the second most wanted new franchise in Japan after Xenoblade.
Cut Wolf: He's the last character completed for Brawl, and I don't think anything has changed to make him higher priority. Everyone else provides more uniqueness than a Fox semi-clone.
Shulk: Smash Bros. is all about showing off the last generation, and Xenoblade was huge. I think Project Rainfall's massive success only shows how much people love this game. Shulk's Monado has a wide variety of abilities that write a moveset for him. Oh, and he's one of the most wanted characters in Japan.
Mewtwo: It's Mewtwo, nuff said.
Cut Lucario: I don't see Lucario being a higher priority than Mewtwo, and I think he competed with Jigglypuff for the fourth Pokemon slot. I don't see him beating out Jigglypuff due to her simplistic design, and Lucario is rather complex with his aura ability.
Chrom+Lucina: The slot I'm more unsure of. I do think we'll be seeing a new Fire Emblem character, and I think Sakurai is fully capable of making the combo unique without causing hardware troubles. Chrom wouldn't be very exciting on his own, but a pair up partner would make them have a very unique moveset.