5 pokemon will just be ridiculous. I'm pretty sure it's safe to say that we're only getting Pikachu, Lucario, Charizard, and Greninja, and I personally think that lineup is perfect.
Mario has 5 reps, and so will Zelda (once Ganondorf returns), so it makes sense to have both series and Pokemon to have an equal amount of reps due to being Nintendo biggest franchises.
We have 29 characters now, and 30 if you're counting Palutena. Brawl had only 35 characters, so if they're sticking to that number, there will be a tough competition for the final five. Hopefully Ness and Lucas are still around, along with Captain Falcon. As for the last two, that's pretty tough. I would guess Falco and Chrom, but that would mean cuts for a lot of veterans.
Let's just hope they're bringing the roster up to 40.
Why would you think we're getting the same amount of characters as Brawl? It was actually a misinformation on what he said about the roster, for he meant he would rather focus on balancing Brawl's roster rather than adding more newcomers. Now that Charizard is on his own, and Squirtle and Ivysaur are out, we'll definitely hit the 50-character roster slot much easier.
If they're having a fifth Pokémon character, it should be either Celebi, Jirachi, Shaymin, or any other small legendary. Would be pretty interesting to play as them. :] Also, personally, I think it would have been really cool if they had made the roster expendable via DLC or something. If they wanted, maybe they also could have distributed stage-sets?
Event legendaries can't be playable in Smash, because it must be a Pokemon you can legally get easily in their game of origin. Besides, Victini was revealed as a Pokeball Pokemon during the direct, and one of the 120 new 3DS screenshots showed Mew retaining its role as a Pokeball Pokemon, so the same can apply to Celebi, Jirachi, Shaymin, and other mirage Pokemon.
Anyway, guys, there's a rumor that's been going on since yesterday, and it's from the same guy who said Villager, Wii Fit Trainer, Mega Man, Little Mac, Mii, and Pac-Man were set to be revealed at last year's E3:
https://gematsu.com/2014/04/rumor-shulk-palutena-set-super-smash-bros#hfRD4FMyrhZMUhmA.99