I love you all to death (Just so I can smash bros with you) (SSBWiiU/3DS)

[Kriven]

Judging by the Smash Bros. franchise trend, both Meta and Dedede will be returning, though their reveal is only mildly guessable. Prince Fluff and Bandana Waddle Dee have decent chances of appearing as playable or assists (and I would not be opposed to B. Waddle appearing as a rare result of King De's side-B).

[Ton]

Meta will 100% be in. That's like saying "Luigi won't be in. He wasn't in Mario 64."
He's still very important to the series as a whole.

[Jermungandr]

I wasn't saying MK wasn't returning, just that Dedede is more likely to be revealed sooner between the two of them.

As for Prince Fluff and Bandana Dee, I predict both of them will be assist trophies at best. Despite being the biggest Kirby fan I doubt the franchise is going to see another spot on the roster.

On the flipside though, I could totally see them doing an Epic Yarn themed stage.

[Ton]

Let's just put this out there: These characters are almost 100% guaranteed to be coming back:

-Yoshi
-Jigglypuff
-Captain Falcon
-Ness
-Sheik
-Ganondorf
-Ice Climbers
-Falco
-Mr. Game and Watch
-Wario
-Zero Suit Samus
-Diddy Kong
-Dedede
-Meta Knight

Once you've made it two games, you're pretty much guaranteed to be coming back. The rest are all natural choices.

[Sir Ethan]

I wish Miis,Klonoa,and Quote were in this. If the other 4 of the ssb64 vets were revealed,then we have 24. add sheik,zss,and the 3 I mentioned and we have 29. Add Ninten and we have 30.

[TomGuycott]

Miis - might have some sort of presence.
Klonoa - Why?
Quote - Definitely not happening.
Ninten - Ness isn't enough?

[Jermungandr]

Klonoa - Why?

I'm guessing because of the game being developed by Namco.

[Darky's Reincarnation]

i see something klonoa related happening, maybe an assist, regular trophy, music, stickers if they are back. there are some klonoa games on the game boy advance, they're all pretty good.

but maybe not, i'm the same guy who thinks maybe no more heroes gets an assist, regular trophy, some music (YES) or stickers if they are god damn back again

edit; ninten is not going to happen, but would love to see his down syndrome design for ness as alternative costume. but i don't see it happening.
mother 1 music on the other hand is something i would love to see/hear more.

i also still want ridley playable, and some part of me still thinks it's going to happen because he's not been announced as stage hazard yet while loads of pictures of pyrosphere has been leaked by sakurai. also his ''an old nemesis can appear any second now!'' probably means that he wants you to think he's a hazard.
please don't be a hazard.

[Ark Kuvis]

Call me an optimist, but I think the only fighter to be "removed" from Smash Bros this time around is Snake. Because let's be honest, Kojima is taking that franchise in a completely different direction, and also not on Nintendo consoles.

So going off Ton's list, I'm just going to list the characters he didn't mention and discuss why they probably deserve to return:

Lucas:

Probably my preferred PK kid, Lucas is the most recent hero of the Mother trilogy. As evidented by Brawl, Mother 3 was represented quite well. It's also the only Mother game released on handhelds, making drawing a stage pretty easy. While I don't think we'll get another rep from the franchise, I think Mother 3 is THAT solid of a game in Nintendo history for him to stay in the franchise.

Ike:

Hero of the Gamecube and Wii Fire Emblem games, Ike is the only "Lord" (he's as commonblood as you can get actually, which sets him apart from the other princes and princesses from the series) who had a leading role in two fire emblem games outside of Marth. He's really popular among western Fire Emblem fans, and he's appeared in a staggering amount of Fire Emblem Awakening DLC. Heck, an actual character in that game is the descendant of Ike himself. While many believe that Ike will be replaced by manly marth Chrom, I believe he'll make the cut in the WiiU and 3DS installments of Smash Bros.

Lucario:

the popular Fighting/Steel type appeared in Brawl as the Generation 4 rep, with advertising pointing toward the newest pokemon movie. While this is true, I think Gamefreak realized how popular the lupine was, and he has appeared in many other titles since. In both Gen 5 and 6, Lucario was catchable really early on, and the latter generation actually highlights Lucario as a prominent mega-evolver. With this new mechanic really solidifying Lucario as important in the Pokemon Universe, I believe he will return. Probably sporting a new final smash...

Wolf:

Debuting in Star Fox 64, Star Wolf has always been a thorn in the Star Fox Team's side. Wolf and his team appeared in a lot of games before Brawl, which supported Sakurai's decision to add him into the game. Since then, the Star Fox team hasn't flown in an original title...though expect a Star Fox 64 inspired stage to appear in the 3DS version, as that game was released since. Wolf's importance as a rival could be enough to keep him, as he does show up again in the 3DS remake. That fact doesn't hold true for a certain blue vixen, who is obviously the only other character in the franchise worthy enough for a place on the roster.

ROB:

The Robotic Operating Buddy is one character I can guarentee will return! He was a huge character in the Subspace Emissary! Not to mention that this little accessory was a key part in marketing the NES to american audiences. His moveset was unique, he's plenty likeable...and deff an important part of Nintendo's history. In a game full of Nintendo All Stars, ROB is as all star as a Smash Bro can get!

[Omega]

If Snake returns you can just bet the 3DS version will have a Snake eater stage.

[Ton]

Ark, I think they're all likely as well, but I thought I'd just say that the ones I listed are pretty much a given. Some notes:

Lucas: He and Ness are really all we need from the Mother franchise, though, being an RPG series, there is no shortage or great characters they could use. if we got Claus/Masked Man, I would be the happiest person ever, but I think we'll just get these two. They're both important characters, they both represent totally different games. Like I said, Ness is 100%, but Lucas is probably going to be in, too.

Ike: Pretty much what you said. I don't think Ike is going anywhere. He's the Lucas to Marth's Ness. They're both very important. Chrom is just a flavor of the week character in the same vein as Zoroark or Midna or Ghirahim. He's popular now, but he won't be by the time the next game comes out. Ike has staying power.

Lucario: As I've said before, Mario needed at least five characters so Pokemon could have five. We got Rosalina, so I think Lucario is safe. Lucario will stick around because A) He's insanely popular B) He's the only Pokemon not from Gen 1 to be playable in Smash C) He's the most popular "mascot" Pokemon since Gen 1. Zoroark's peak is over and Gen 6 didn't have a mascot to push, so Lucario is still in the consciousness. He'll probably make the cut.

Wolf: Aside from Snake, Wolf is, in my mind, the most likely to get cut. But that doesn't mean he will. He's the Star Fox villain rep because Andross is a floating head with hands. That doesn't really make for a good fighting game character. Wolf, as the personal rival, is the next best thing. His moveset is a bit bland, but that can be tweaked. We'll see,

ROB: Another one who probably isn't going anywhere. There are a lot of naysayers when it comes to ROB, but I don't really see a good reason to lose him. He's fun, he's interesting, and he's unique. He fits well with the "retro" characters.

And to add my own to the list:

Mewtwo: I think he'll be back. He's been pushed hard as the closest to a mascot in the new Pokemon games, Mega Evolution has brought him back into the public consciousness, he's on the soundtrack for Pokemon X/Y, he was featured heavily in the new movie, and Sakurai has already said he was being considered. Even if it's X/Y Mega Mewtwo, I think he'll be around in some form. And it'll be a big deal, because people were pretty disappointed what he was removed in the first place.

[Virtuaboy123]

Miis - might have some sort of presence.
Klonoa - Why?
Quote - Definitely not happening.
Ninten - Ness isn't enough?

-I'm thinking a mii parade assist. They'll all scatter about and maybe look like the mii's you have saved on the Wii U.
-Doubting any Klonoa anywhere.
-Quote ehh no...
-Ninten should get his own trophy maybe showing that him and Ness are different. And fixing all that mess.

Also I think everyone in brawl will return. I think Snake will surprise everyone by returning and probably a bit nerfed (He was heavier than ganondorf, with tons of indirect tricks)

As for Mewtwo I'm hoping his mega forms will be Zelda/Sheik like.

Also hope we get Slime or Loto from DQ, I mean Fortune Street exist. Also DQ 9 and DQ 10 were both released on Nintendo systems.
Dragon Quest also appeared on almost every major Nintendo system too (besides N64)
They'd be a third party rep which is the only problem otherwise they are pretty deserving of one at this point.
edit
and Gamecube, I swore DQ 8 had a gamecube version. But its been on Nes, Snes, GB, GBC, GBA, DS, 3DS, Wii, Wii U with multiple entries in each system too!

[TomGuycott]

I really, REALLY don't expect any other 3rd party characters other than possibly Snake. The 3rd party characters who have been in Smash games are LEGENDARY video game characters, and most of what I see people suggesting all the time is characters so obscure nobody would recognize them, sans perhaps Pacman.

[Kriven]

I think Pac-Man has a decent chance, and I also think Tails has a higher chance than any other third-party character not already utilized (except for Pac-Man) in the franchise because of how buddy-buddy Sega and Nintendo have been lately and considering the success of the Mario & Sonic franchise.

As far as cuts go, I think Lucas and Wolf are the most likely to go. Sakurai doesn't really like Earthbound and never intended for the franchise to have two reps. Ness only returned by popular demand, and I think he'll do so again. Lucas doesn't bring much to the table without being altered, and he's kind of an obscure character to the world in general. He might return, but I wouldn't be surprised if he doesn't. Same for Wolf, who hasn't appeared in a new game since Brawl and even there his inclusion felt a little weird.

Snake may not return, but I'm honestly not sure. He may go both ways.

Other than them, I think Lucario and Pokemon Trainer are the most likely to leave, but I don't see Lucario going anywhere, and now Red and Charizard have Pokemon Origins going for them (as well as MegaCharizard X and Y). I do think Mewtwo will return, and we may still see a Black and White rep.

I no longer think Wind Waker Ganondorf will be arriving, unfortunately. I don't think Ike is going away, I think Roy's fan status might allow him some backdoor access.

Here is what I see as possibilities broken down more simply:

Returning from Melee:

Mewtwo - X and Y, Double Megas, Fan Status
Roy - Awakening DLC, Fan Status

Cut from Brawl:

Wolf - No longer relevant
Lucas - No longer relevant, not universally relevant, Sakurai hates Earthbound

Returning from Brawl:

Wario
Yoshi
Diddy - Specifically, his importance in new DK games.
ZSS
Ice Climbers
Ganondorf
Meta Knight
King Dedede
Falco
Ness
Jigglypuff
ROB
Mr. Game & Watch

Could be Cut:

Pokemon Trainer
Lucario
Snake

Newcomer Possibilities (asterisks around who I see as the top eight most likely):

Bowser Jr. - Miyamoto's baby
Toad - NSMB franchise, 3D World
Tetra - Wind Waker HD, intended for Brawl
Dixie Kong - Tropical Freeze, intended for Brawl
Ridley - Fan favorite, Other M
Palutena - Fan favorite, Sakurai favorite, Uprising
Medusa - Fan favorite, Sakurai favorite, Uprising, Legacy Villain
Chrom - FE:A
Prince Fluff - Epic Yarn
Bandana Waddle Dee - Completes the set of Return to Dreamland player characters
Mii - Sakurai mentioned customized characters, Show up everywhere
Pikmin 3 Captain with Rock and Flying Piks -
Zoroark - Black and White were still relevant during the early phases of Smash development
Dillon - Pretty popular, represents the 3DS and eShop
Pushmo Guy - Pretty popular, represents the 3DS and eShop
Pac-Man - Namco working on the game, Video Game significance
Tails - Sega and Nintendo's relationship strengthened, Video Game significance
Tingle - Three games this past generation, Nintendo seems to love him
Shulk - Xenoblade
Little Mac - Punch-Out Wii, Legacy

Of them, I think these eight have the best chances:

Pac-Man
Dixie
Bowser Jr.
Shulk
Ridley
Mii
Dillon/Pushmo
Palutena

I think Mega Man is representing the NES-Retro character this time, and I think Wii Fit Trainer, Mii, and Villager fill in the Avatar/Peripheral slots utilized by G&W and ROB. It's possible we might get Little Mac and Takamaru, but I'm not so sure.

Wishlist:

Muddy Mole
Diskun

but they won't happen.

[Ton]

Where has it ever been insinuated that Sakurai hates Earthbound?
I don't think Roy will be back. Granted I'm not as aware of the FE fanbase as other franchises, so I don't know if there's been any clamor for him to return.

As for Chrom, Fluff, Bandana Dee, and Zoroark, one game does not a "major character" make. They have to make a strong impression and return enough to be a regular to the series. Like Diddy or Wolf or even Rosalina at this point. All of those characters you listed have been in one game. There's no reason for them to get such a major spot in a Smash game.

Dixie, on the other hand...

As for Bowser Jr, he was my choice for a new Mario character, but now with Rosalina in, I think that's been squashed.