Goku’s Corner has a fan Q&A session all about Raging Blast 2 with Ryo Mito, the game’s producer. There is not a whole lot divulged about the game that is not already known, though there are confirmations on new modes, about 20 “new characters” (meaning characters and forms that did not appear in the first Raging Blast from last year), and a few new official screen shots.
In related news, Paikuhan, Nail, and Future Gohan have been revealed as playable characters in the game. All three have appeared in previous video games, but were not included in the first Raging Blast.
UPDATE: Namco-Bandai has released new images of the game for Comic-Con, confirming the return of Super Saiyan 3 Broli and Super Saiyan 3 Vegeta from the first Raging Blast: