Yes he is saying that just upping the roster isn't enough BUT he is also saying that from a balance point of view 39 is the limit, not a technical memory limit but a gameplay design limit.
If you want a perfectly balanced game, you either play as just 1 character, 2 characters that are similar and have equal potential, or 3 characters with equal weaknesses. Sakurai realizes that. He is just preparing us for the game to not be totally balanced. I mean, there have been all kinds of poorly balanced characters in each of the 3 smash bros. game thus far.
Also, Sakurai is probably talking more in terms of content and stuff. He is saying he won't add as much as he did in the previous 3 smash games most likely.[COLLAPSE="I mean, in Melee, we got:"]14 new characters, loads of new attacks for many of the original 12, a new "side B" attack, wall teching, wall jumping, tether recovery, all kinds of new advanced techniques, new "Z airs" for some characters, 2 new grab angles, grab pummels, 280 or so more trophies, an adventure mode, an all-star mode, a multi-man stadium mode, a home-run contest mode, 51 event matches, 24 new stages (also 2 redesigns, and 3 Smash 64 stages), loads of "Special" multiplayer modes, new common enemies for the Adventure Mode, more character data, more items, more Pokéball Pokémon, a new time limit option for stock mode, the coin mode multiplayer mode, the bonus mode multiplayer mode, the new stamina mode multiplayer mode, new and improved graphics, new and improved lighting, new physics on a new in-house Nintendo engine, and all kinds of new options, all of which weren't in Smash 64.[/COLLAPSE][COLLAPSE="In Brawl, we got:"]17 new characters (and 4 cut characters, and 1 redesigned), some new moves and tricks for returning characters, footstool hopping, roof teching, wall clinging, gliding, all kinds of new advanced techniques, a brand new online multiplayer, a multiplayer-event matches stadium mode, a multiplayer multi-man stadium, mode, a multiplayer event matches mode, a multiplayer home-run contest mode, online multiplayer stadium modes, a boss battle stadium mode, a brand new story mode that you could play with a friend locally, mix and max "special" modes where you could apply all kinds of changes, new Pokéball Pokémon, a Pokéball-esk items called "Assist Trophies" with "Assist Trophy characters," new common enemies, new stickers, a sticker ball where you could power up your adventure mode characters, new and improved graphics, new lighting, new physics on a new engine (the Havok engine), and all kinds of new options, all of which weren't in Melee.[/COLLAPSE]The only obvious additions to that list are more of everything listed (stages, characters, items, etc.), maybe up to 6 player gameplay, more online modes (up to 4 players?), and some new modes and stuff. However, if you limit yourself to really just that, you aren't being creative; you are just adding on stuff and "updating" that game. Sakurai doesn't want to do that, and we don't want that. Even if the game fails to meet our expectations, at least we know that Sakurai was trying to give us a brand new smash bros. experience, like all smash bros. games before it. That and we can always mod it and turn it into a golden game!
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