I want Isaac. And Sailor Moon.

=P

I think they can replace Sheik now by a more important Zelda character. Like Tingle.

My top 10 characters I want in Smash 5:

10. Erin Jaeger
9. Spongebob
8. Yui Funami
7. Nick Wilde
6. Donald Trump
5. Futaba Sakura
4. videogamedunkey
3. Miguel_Zorro
2. Female Shovel Knight
1. Ridley

(This list is 57% serious)

Given Splatoon's popularity in Japan they will undoubtedly add an Inkling even if it's just a Smash 4 port. It is likely they add an ARMS character to promote that game as well. Usual suspects as possible additions: Bomberman, Rayman, Simon Belmont, perhaps they will finally listen and add Ridley.

Also, it won't happen, but I would sacrifice three goats to Ba'al if they actually put Professor Layton in the game.

With all the third party characters I would say there are quite a few that could be in the next smash. Inklings and someone from ARMS is pretty much a given.

Other than those, these are the ones I hope for:
John Raimi
Battalion Wars/advance wars character
Doshin
Phoenix Wright

Shantae coming to smash. A proper single player mode like the one on the Wii.

Yooka and Laylee

Just like Snake and Cloud was for psasb1? :p

Ice Climbers return as a playable character. They retain their moveset from Brawl and have a new stage based off of their original NES game.

Bomberman becomes a new fighter. His moveset consists of throwing different types of bombs. i think he has a chance now since Konami did make Super Bomberman R and then made a substancial update to Super Bomberman R, and its exclusive to the Switch.

Inkling Boy and Inkling Girl will both be new characters. Inkling Boy will use a splat roller and Inkling Girl will use a splattershot. Their alt costumes will feature different color inklings as well as weapon types, although they will all function the same.

Alm and Celica both become new fighters. and they both have identical movesets to Marth. because of course they fucking will do this

Ice Climbers