First, he explained the construction of the team, saying they were "structured like mercenary horde." Since Sakurai works as a freelance designer (his company is really just two employees, including himself) he assembled the 100+ person team for Smash for this project, and not everyone was full-time. Moving onto the most obvious topic: character selection. With Smash's extensive roster, Sakurai said most of the characters were "finalized in planning documents" before production even began. One of the few exceptions was Sonic, says Sakurai. "To tell you the truth, the decision to include Sonic was not made until 2007." Apparently, even some Nintendo characters could not be included because of "rights issues" -- we're not sure which characters he may be referring to.
One of the most difficult aspects of assembling this varied roster was creating a consistent aesthetic. Even though "the Wii is not a high-definition console" it still offers a visual fidelity that exceeds the simple nature of many of the roster's official character models. Having photorealistic models fight cartoon models would appear unnatural, so he endeavored to make some small changes to help bridge that gap. Take Mario who, in Nintendo's official model, has bright blue overalls; in the Smash model, he's wearing denim overalls, with more detail on the stitching. Same for Pikmin's Olimar: they replaced the official model's flat suit with a more detailed spacesuit replete with straps and knobs. Pit from Kid Icarus was another situation entirely: the character model hadn't been updated in 20 years, so they had to redraw him entirely. The new model looks nothing like the old cartoon. Sakurai says they looked at the most recent Link model from Twilight Princess and considered the evolution of that character when considering how to update Pit.
Gallery: SSBB gallery two
Moving onto the motion and animation in the game, Sakurai revealed that he used a posable 4" Microman figurine (abundant in Japan, apparently) to show his artists and animators the basic poses he wanted for each character. He would take 30 to 50 pictures for each character, creating an inventory of available poses that would later be animated together "without the aid of motion capture, everything was done by eye." A series of slides show the fidelity between his Microman pictures and the final Smash character renders, revealing a painstaking process that nevertheless gave Sakurai unique control over the art without a lengthy trial and error process.
The more intangible elements of each character, like weight and inertia, Sakurai did all by hand. Consider the example he gave comparing the jump animation of Mario and Samus in both character's original games. Mario returns to the ground quickly, while "Samus' jump has more float to it than Mario's." The reason for this isn't because "Samus' games take place in outer space" (there goes our theory) but because "players needed to be able to fire at enemies and doors from an arbitrary height" in Metroid. He noted that in the Sonic games, the character transitions from a relatively slow walk to a very fast run, and that transition is "exhilarating" for players. Inversely, Snake is "probably the slowest" human character in the game, but powerful attacks and a variety of weapons balance out that handicap. Above all, when constructing a character, Sakurai says your "initial thoughts on the subject are truly invaluable." (Sounds to us like someone read Malcom Gladwell's Blink).
Lastly, he discusses the game's incredibly popular site, the Super Smash Bros. Dojo. While they've had homepages for the two previous games in the series, Brawl is the first title to get one outside of Japan. In fact, Dojo is published in seven languages, updated five times a week for a total of over 230 updates since its May 2007 launch. At the peak of the site, it got as many as 1m page views a day, and 5m page views a week. Says Sakurai, "If we hadn't launched Super Smash Bros. Dojo, there would not have been this much buzz about the game regardless of the franchise history."