I meant "Yes, he (Snake) is a secret character", not "Yes, he (Sakurai) is putting characters on the Dojo". That was a separate interview. Although the two kind of go hand in hand now, don't they?
But now we're on that topic anyway, so here goes. In regards to the "will you reveal secret characters" interview, I seem to recall that the gist of Sakurai's response was "people are going to learn about all the secret characters immediately from the internet anyway, so I would rather they hear it from me with a bunch of fanfare". This interview predated the new-and-improved Dojo by a really long time, so people didn't make as big of a deal out of it as they would have if the same thing were said today, which is probably why it isn't common knowledge now.
Unfortunately the Japanese interview translation thread got unstickied ages ago and seems to have sunk off the forum, so I can't check the exact wording anymore. But the point is, I'm pretty sure that Sakurai has never led us to believe that he wouldn't unveil secret characters, and may very well have implied the opposite. People just tend to
assume that he won't because they're hung up on the word "secret".
*sigh*. I really wish that old thread still existed. It used to be the centerpiece of the entire Brawl forum when we had nothing else to go on. I'm sure it would have still been useful today if it were still there.
EDIT: No wait! It DOES still exist! Hooray!
http://smashboards.com/showthread.php?t=72642&highlight=translation
"#251-260: Sakurai in response to an email asking that everything be unlocked as a default = 'Well... that is a tough question. As long as the internet exists, all secrets will be revealed quickly. Sometimes even before the game comes out, even. Secret characters are one of the fun parts of Smash. Although you don't want to find out until the very end, I guess [literally: 'after all,' so there is no doubt in this statement] I'll reveal them. Again, just like "Smash fist" [literally: 'Sumabura ken,' the name of the Japanese SSBM site?] I can't just hold these characters back. '"
Okay, so I guess it's not quite as clear-cut as I remembered it. But the premise still seems to be "the secret characters will be leaked through the internet no matter what, so I might as well reveal them myself".
The poster also says that it was implied by Sakurai that Snake and all other third-party "guest stars" would need to be unlocked, but he never put the exact translated phrasing up.