Krunch returning would make sense, as a Kremling he's the only original character that couldn't be used in a Rare project. Dixie and Tiny rplaced Banjo and Conker in the DS game, so no surprise there, either.
There was actually an interesting Smash rumor going around on GameFaqs the other week that people compared to this.
Guy claimed to be a Namco-Bandai PR representative with insider info.
Claimed Takamaru, King K. Rool, Little Mac, and Ridley were all in, and Dillon, Ghirahim, and Shulk were being worked on. There was also mention of a new character code-named "Debu" which is supposedly from the new Yoshi Wii U game.
The interesting thing for me is that he also revealed the full roster for the JoJo Bizarre Adventure PS3 game which he also knew due to his position of working to possibly localize it. So far, the list hasn't been wrong, but then again I don't think we've seen any new characters since it was posted.
There were basically three proofs he posted he claimed would prove his legitimacy:
* The roster for JoJo would check out. The Jump Festa trailer didn't contradict it, although it didn't show any new characters either, but they're revealing characters for that monthly about so we'll see.
* There'd be a Nintendo Direct on Brawl's Japanese release that would be a retrospective of the Smash Series with a bit of new information. He said a trailer was unlikely.
* "Debu" would be featured in the Yoshi game as a major character, assuming Yoshi Wii U is true.
As for my thoughts on the smash list:
Takamaru
He makes sense. He's been a popular choice for Smash Speculation during the run up top brawl, and with his mini game in Nintendoland and the remake of his game in a recent Samurai Warriors title, there seems to be a lot of energy at Nintendo around the character that could lead to a revival.
King K. Rool
Makes sense with the growth of the Donkey Kong franchise to prominence, but aside from some Mario Sports titles, he hasn't really appeared since Rare's departure - being replaced in the series by new villains without a single figurehead.
Little Mac
Hugely demanded character whose series recently underwent a revival. Mostly western demand, but demand recognized on Japanese smash communities.
Ridley
Metroid needs a second character, and Ridley makes the most sense in a series with a (mostly intentional) dearth of significant characters. Also, massive demand.
Dillon
The commonly agreed upon symbol of Nintendo's new digital efforts, could borrow some moves from Sonic.
Ghirahim
A strange choice. A popular addition to a recent Zelda game, but not significant outside that one title. Still, the same argument could be made about Shiek.
Shulk
The face of one of the few character driven IPs Nintendo created this past generation- he makes sense.
"Debu"
The character will not have been around long enough to be certain if he'll take hold, but he'd fit in with Roy and Lucario as characters added to promote new titles.
Notable absences Palutena, Mii ... But there's probably more newcomers than the ones on the list even of this is true.