At the end of the day, big names and small names are a delicate balancing act in regards to roster making. In general, the best chance is to specifically gun for a character to make it into the base roster for the upcoming game, whenever it happens.
Well, that and we still haven't quite gone down the pecking order of companies yet. As of now, the smallest name companies who have playable characters are Atlus and Platinum, and even with that Sak had openly acknowledged that big name series/company inclusions on the Japan side are running low.
In any case, I wouldn't be hung up over it. Perseverance and patience will be rewarded at some point, especially if seasons increase by the game.