I can only think of Raymond Bryce, and if you ask me, he would be the perfect replacement in case Snake doesn't make it to the new game.

And before you guys say something, remember, Monolith Soft is now first-party :P

I have a suspicion Professor Layton might make it in, this time.

Beacuse she is AMAIZNG and just just.....PERFECT! 

This guy would fit pretty well I think

Isn't the Professor Layton IP owned by Level 5? When will Youkai Watch be released on the west? (from now on, every time I talk about Level 5 I will ask about Youkai watch, you have been warned :) )

Bayonetta isnt likely, just fans want her in. Its the same with Geno. Likely=/=Fan Base.

 Bayonetta is third party, it doesn't matter if she is an exclusive. It makes no sense for her to be in the game before many others. If we are talking third parties, there are plenty of others that would get in way before her. Lastly W101 would be in before her as nintendo owns the IP but they are just trophies

and the main character from an upcoming major exclusive. that's far more than sonic and snake ever had.

lol keep it in your dreams :P  Also Dillon is already in the game, he's an assist trophy. I wanted him to be playable.

Not shulk, xenoblade X new main character.
splatoon girl
Some W101 chars together playing like ice climbers

I agree with you, but that wasnt the question the OP asked...