He didn't know it would be revealed at E3 2011, but he did know he'd be making the games, unlike Brawl where he didn't even know he'd be making another Smash Bros.
Late 2013 would be pretty cool and I'd probably ask for it as a Hanukkah Present. It would then be only two years, so hopefully the game is good. Project Sora could just use Brawl as a starting point for SSB4, adding in new characters, stages, assist trophies, music and an awesome online. Since it is two games, do you think they could get delayed, be a simultaneous release right on schedule, or do you think one will come out and then a little later, the other one? Sakurai could have one big team for the Wii U and another for the 3DS.
Which version are you going to get? I'd get the Wii U one because it will probably get more things (besides, cartridge games can't even do DLCs) and my brother and none of my close friends have a 3DS. The only person I know in real-life that could play a 3DS with me in the future could be my brother, but that's it for now. With the Wii U, friends could come over and we could play it. It should have backwards compatibility with the Wii Remote (and maybe even the Game Cube Controller), making things easier. Sakurai also said the 3DS one would be a more personal experience.
I've also shrunken my wishlist for characters down to 53, being only a 14 character increase.