I'm not even talking about starting roster, though. I'm saying that those characters were revealed earlly on the Dojo to build hype. The remaining roster will be revealed after the game releases, beacause they aren't very hypable...We still have no idea of the starting roster. Personally, I think only 14 characters will make it, mostly based on Sakurai's choice to only demo 14 at a time.
And frankly, I don't consider the commercials as substansial reason for the characters to be on the starting roster.
Snake and Sonic are big back bone characters to the games potential sales boom. But to only have 15 new characters, 1 of which I think is a joke to consider new, and show off 12 of them is a bit of a bold move, and they could have at least saved some characters for November and December, which were awful update months.
The issue is that if we knew about these 12 characters early, and the leaked roster had all the crazy newcomers like Pokemon Trainer, Deded, Pit, olimar, MetaKnight, Snake, and Sonic. We would be going crazy over the 35 character roster, but it'd be the same roster!