The complete list of system and character changes for Guilty Gear XX Accent Core Plus R is up! You can find it at the official Guilty Gear homepage in .pdf format. If the site is getting hammered right now, it has also been mirrored on filestorage. 52 pages worth of changes! Who would have thought so many adjustments would be made!
So far, various members of the community are translating the changes in different places, so it’s a bit difficult to find them nicely compiled into one place. Shinjin has been doing what he can in listing the changes on Bitter Harmony, and newer changes are constantly being posted to the Dustloop +R changes thread. Start on page 6 to see the changes reported from the changelog.