The entire Super Smash Bros. for 3DS and Wii U is set to be revealed in the next issue of CoroCoro magazine on August 12. The upcoming preview for the next issue of the magazine teases fans with the following message (thanks to this translation):
We’re including an additional jam-packed volume containing all of the characters and stages for the up and coming 3DS version of Smash Bros.!!! Keep your eyes peeled for when it goes on sale!
The Japanese release date for Super Smash Bros. for 3DS is September 13, so there isn’t too much time to reveal all the remaining characters. Let’s see what’s announced before August 12!
UPDATE: CoroCoro has clarified the situation and has stated that they will only show everything we know so far, so don’t expect a full roster or new stages. Sakurai will continue to reveal more as he sees fit.