Daisuke Ishiwatari, general director of the Guilty Gear series, has taken to Twitter to explain that the new Guilty Gear will be a "complete reconstruction of the franchise." In a lengthy post to fans, Ishiwatari said, "The core concept this time is unlike those of the past titles—it is neither 'evolution' nor 'returning to roots'; nor is it an addition or subtraction of elements from existing titles. What we're pursuing is a brand new experience for Guilty Gear."
Since the title was just announced, there isn't much that Arc System Works can currently talk about. From the looks of the teaser trailer, I'm not exactly sure what is different about the game, but then BlazBlue Cross Tag Battle is a dramatic overhaul of BlazBlue. For all intents and purposes, this could be something similar.
You can read the full statement in the embedded Tweet above. It's rather lengthy, though it looks like Arc System isn't resting on its laurels here.