Probably Shulk cause Monolith Soft retweeted this announcement in particular, but guessing this is the last newcomer video before release I also expect some epic montage of smash modes and nostalgic music and poses too.
Also... I don't think this is super duper probable but I kinda just wanna say it so I can be like "Oh hey, I thought of that" just in case it happens. It's a little suspicious this video is taking place right after Evo, sponsored by Nintendo. Maybe the trailer was made with a few variations based on popular veterans featured in Evo! Like... maybe if Ice Climbers do something cool, they'll wanna show them in the trailer too? Or if... well I dunno about any other melee veterans that would be starters. But just wanted to say it haha...
Also! Since I expect Shulk, I looked up a lets play to learn more about him. I would've never guessed he had an english accent! Pretty interesting.
And just in case it isn't Shulk somehow...umm...maybe Ridley or Chrom or Robin... I don't really believe the gematsu stuff, it's full of safe guesses so don't think I'm basing my logic off that.
Anyway. Excited to see Shulk soon!