A follow-up to Persona 4 Arena has been announced. The sequel-of-sorts will add two additional fighters: Yukari and Junpei, both from Persona 3. They'll feature updated designs to reflect the time gap between Persona 3 and 4.
As in Persona 3, Yukari will use her bow and wind-type "Garu" skills. Junpei's attacks are all based on baseball, with every successful attack unlocking potential buffs during battle. In addition, every existing character will be updated with new moves and Skills, with each character able to access new Persona cards. Finally, every character minus Elizabeth has been updated with a "Shadow Type" as well. By earning SP, players can unleash "Shadow Rage," which allows for unlimited SP Skills, Skill Boosts, and more.
The update was announced for Japanese arcades, but given the game's popularity on console, it seems likely that the new game will find its way on PS3 and Xbox 360 eventually. For a full report on what's new, visit Shoryuken.