this was already discussed in the first live interview.
they were asked why there wasnt a 14 representative in the second dissidia and they said it was because they do not feel the game has a solid hero or villain worthy of representing the game yet.
i personally thought it to be odd because of the red and black Darth Vader guys already in the game but it did come directly from Yoshis mouth.
they want to wait until 2.0 to flesh out some real characters to be proud of.