Now before I get started I would just like to say the characters boxed in blue starters, red are unlockables, greens are starters with new movesets and yellows unlockables with new movesets
If we were going to get the average added on that each game has seen to this point which has been between 12-14 character slots. (Including characters that have multiple characters per slot) I wouldnt be to surprised to see something along the lines of this roster.
With returning franchises instead of getting new characters receiving reworks or separations.
Luigi further separated from his brother. (we already know that Bowser is getting changed a bit)
Gannondorf finally getting his own moveset.
Toon Link perhaps delving into the very wide arsenal that is the Zelda franchises.
You might see small move changes in other series but nothing to the scale as I expect for the ones mentioned for they generally already differ enough.
Pokemon Trainer I could see be used as a way to include newer pokemon or perhaps pokemon that dont have a generation representing. Though I wouldn't be surprised to see one of his 3 stay such as Charizard, or to see Lucario thrown into one of his possible 3 (why waste a good moveset though you lose some of his mechanic).
Mewtwo being included due to his recent new form reveal and the fact that during brawl we kind of lost our legend.
Lucas getting a revamp simply because there are a lot of choices to choose from in the Mother franchise and he doesn't need to have these moves that are slight variations of Ness' moves. (Although seeing a move maybe changing on Ness wouldn't be a complete surprise.)
And that covers reworks. Next on to the new cast. With Pokemon and Fire Emblem being the only returning franchise to get new characters. The reason for that being is the other franchise are a mix between basically having their main cast already added and the left overs either being one offs, or side characters.
The exception being franchises like Metroid which you could add someone else like Ridley, but seeing Zero Suit added last time I feel the series is well represented as is. (If Other M was better received and/or they had another Metroid already announced my thoughts would probably change but I wouldn't be surprised to see a new rep if it does happen though.)
Another being Donkey Kong. You have your two characters that you always expect in its series. If the game were made back during the SNES era I would say someone like King K Rool would be a shoe in, but its not sadly.
The last being Fire Emblem, with Ike and Marth being Fairly Iconic characters with great movesets. Why add another to the fold? Well Awaking was so well received and FE keeps releasing at the very least good game after good game, to see their franchise get one more if they can find a way to make it unique would seem to make sense. So Robin or the Avatar would make sense to me, perhaps someone who more focuses on teamwork of other units from this game and call in attacks. But who knows I might be crazy and dead wrong.
Also wouldn't be to surprised to see the older Ike and maybe a few tweaks to his moves.
Then we have new franchises being added which I tried to think of characters and their franchises that could add something to the game and give out a unique moveset.
Takamaru being your retro character that not a lot have heard about. But his games doe give you several items that could be thrown into his moveset to help him differ from the other sword users. (Personally would of went with Mike Jones but he was never in Japan and his 2nd game left a bad taste in most people's mouths, but he had a good variety of items to use)
Starfy could fit your new cute and kinda new in other countries role, but he has a history that he could draw from.
Saki would be very different from anyone else in the game and his series kinda does have that whole the fans cried for it enough we gave them another one. (If he doesn't make it in though, I wouldn't be surprised to see Shulk fill this role. But iffy since he might just be a one off, though the project rainfall and X might be reasons to get him in over Saki. Regardless I fell the both fill a certain gap.)
Ray MK II This being more of a fan pick with the Custom Robo. Its games were somewhere between decently received to well received. Not amazing per say but still brought something unique to the Nintendo console and could bring something unique to smash with its wide variety of different weapons. (However if he doesn't make it, I wouldn't be to surprised to maye see Chibi-Robo take this spot)
Little Mac has been a wanted new comer for awhile and while he might have a slew of items to chose from there is a lot that goes into boxing and if they expanded his boxing moves I could see him being a well received character.
Isaac while indeed another sword user also has his magic to bring to the field which is something we dont see in other sword uses. (Seeing an older or Matthew instead wouldn't be too surprising)
Andy has a well established series and while he might not be the main character in all of them, he can generally be the most recognized. (Although seeing someone else from the war series take his place wouldn't be to surprising if to maybe hype a new game per say) The games being well received and honestly he could offer a very different moveset more counting on the units that were available to him in the game.
Mii is basically something else to represent the popularity of the Wii and if it were to use moves from the games it were included in, its moveset could be about anything. Who knows maybe even an easy squeeze in of hey lets just take one move from each character that could fit and throw him on this guy.
Sonic I see either him or Snake making it back.
Pacman I dont like this character making the cut but with Namco helping with the game, him having a long history, and also appearing in other Nintendo games, he sadly seems to be the obvious pick. (Personally would rather see maybe Simon Belmont, or someone from one of the first 6 final fantasies or even Crono. And while I don't deny their chances, I dont see it as likely as Pacman. I hope I'm wrong.)
Now some of you will probably say that roster is to big. You might be right 47 slots, and 51 characters total. Though it does follow the pattern of the amount of characters added from game to game. Though I could see maybe 2 of them getting cut to bring it down to 45 and 49.
However lets use the flip side and say cuts happen and the roster being smaller than that. I imagine it would look something like this
Toon Link getting cut due to Link covering the most iconic items of the Zelda series and perhaps giving regular link a speed increase.
Then cutting one peson from Kirby and Star Fox, Metaknight seems to bring more to the table than the King. Where as Star Fox I could see going either way.
Finally Ike getting cut and perhaps a good deal of his moveset being given to Gannondorf.
I guess share your thoughts, hope you enjoyed it.
I prefer the first one.