True. If the leak is valid, though, and there are indeed 5 new characters left (not to mention the returning veterans), then I'm not quite sure what Sakurai and Nintendo are waiting for.
5 new characters could easily be 3-4 new character videos. Yet, we're already just 3 weeks away from the release of the 3DS version in Japan, and will therefore likely discover the official roster at some point in the week leading up to the 13th.
Nintendo has only 10 more weekdays to reveal a new character before the possibility of an official leak starts to become incredibly likely. I would much rather be informed of the new characters via their official reveal videos instead of from some random guy who got his hands on the game early and took a screenshot of the roster.