When they claim that this game will feature not only new characters but also new moves, new stages, a new fully voiced story and all the old stages rebuilt along with a new HUD, it being DLC/expansion almost certainly seems out of the question.
http://japan.gamespot.com/news/story...0400513,00.htm - HQ images... with Gamespot watermarks.
Oh BTW... Tsubaki's weapon looks like a dagger/knife.