Back before X/Y came out, one of the main Pokemon designers even mentioned how he thought Greninja was one of his favorite designs.
Anyway, was looking through an old rosters I made in 2012 and comparing it to what we know now...
* I stupidly thought Lucario would be cut. Yes, it's stupid since he was popular still being featured in BW2 advertisements. I didn't know he'd be getting a new "Mega", or what a "Mega" even was, in a few months either.
* I guessed Snake would be cut. Seems he will be, too. This was before all the stuff with Hayter being replaced and such, I just felt having Raiden in PSABR and Snake in Smash would feel sort of weird.
* I guessed every veteran other than those two from Brawl would return. This was before we knew about the difficulties with the 3DS Version that meant the Pokemon would be cut. I also thought Mewtwo would return, and this was before he (or rather, she) was revealed to be returning in the upcoming Genesect Movie. Also with Link I thought he'd be his SS design, which didn't happen.
* Takamaru would get in. Guessed he'd be a stance change, switching between using his sword, and more ninja skills + shuriken. I still think he can happen, although I'm thinking he might end up being DLC.
* Little Mac. Got it! Pretty much guessed he'd be the traditional Boxer. I actually thought he'd have a Counter move and, when used successfully, would gain Stars powering up his other specials.
* Shulk. I was in Xenoblade HYPE mode. And it seems he'll come true! I saw him playing like Ike, a heavy-sword user. His unique gimmick was the Xenoblade would charge up, during which he'd have no Neutral B, but when charged, he could either unleash a huge slash across the screen, or buff his stats.
* Barbara Bat. I was hoping she'd bridge the pond by now, I wanted her in as a less traditional female character. She did have a new game, Japan-only, recently though, and we haven't seen her AT as far as I know...so, maybe? She'd have rhythmic moves, but I guess the Chorus Men, if they're in, would cover that.
* Tingle. The dream is dead. My idea is he'd be his own series and draw from the Tingle games...he'd be unique in that by racking up damage he'd gain Rupees, and lose them when hurt, and the amount of Rupees he had would influence how powerful his attacks are as opposed to the damage the opponent has. His Specials would use up the Rupees, such as calling one of the bodyguards to attack from him and acting like an Ice Climber.
* Mallo. From Pushmo that is. Since then he's had another Wii U game, and I think he still has a chance as a surprise character. He could pull blocks from the background to make platforms, and use as shields, an unorthodox character.
* K. Rool. Still could happen, maybe. He was like D.K., heavy but fast, and could move crates and barrels without losing speed like D.K. Had his cannonball toss, crown throw, long jump, and the blunderbuss which would shoot out the purple gas from DKC2 that would mess up controls.
* Ridley. Also could still happen. He'd have a mechanic when he'd normally move around on all-fours, and have a new model slightly based on his mid-form in Other M, but briefly could take to the sky and grow wings changing up his moves.
* Medusa. I wanted a female villain. I wouldn't be surprised if we get another KI Uprising rep in Smash 4, but it probably won't be her unless she's a Palutena clone. My idea was that she was a powerful sorceress, with moves based off her generals, like summoning fire, and shooting forth bouncing snakes.
* Dark Pit. Well, it looks like he may happen. He was actually wholly unique from Pit, able to switch between the Uprising Weapons on the go, a bit like Vaan from Dissidia.
* Genesect. He's a Pokeball now, but during making this roster, he was the star of the new movie, and I assumed he'd have a role in XY. I guessed there'd be a new "Ancient Form Genesect", which he'd switch to for a Final Smash. He'd have high-powered beam attacks, and could switch between the Drives.
* Paper Mario. As a counterpart to Toon Link, he'd be more unique than Mario, using his hammer, and various paper skills like the airplane. I still want this to happen.
* Yarn Kirby. The third "material" character alongside Toon and Paper, wouldn't have his copy ability, but his yarn whip instead, and various skills from Epic Yarn. Doubt this will happen since that game was a one-off.
* Pac-Man. Got it! His moveset was summoning the ghosts for all his moves, didn't think Sakurai would go all-out with the Namco Love.
* Mega Man. Got it! My idea for him was he'd have the Mega Buster, Slide, Rush Jet, and Teleport as moves. I didn't guess he'd have the various Robot Master moves, instead if he hit the opponent with a fully charged Mega Buster, he'd gain a projectile version of one of the character's attacks and change colors (like for Mario he'd get the Fireball, but for, say, D.K., who has no projectile, he'd fire off a giant fist). He could then use Taunt to switch back to the Mega Buster to get a new move.
* Bomberman. Still want this to happen...he'd replace Snake as Konami's rep. He'd be all about laying down bombs, which he'd be vulnerable to as well so you had to plan carefully where you placed them.