"Even though the distortion has disappeared, the scars remain. The lost parts cannot be restored. The pure earth will inevitably experience distortion once again. Since that banquet, the earth has officially entered a period of turmoil, and earthquakes will occur more frequently than ever before. Moreover, there is a chance for 'Crazy Earth' and resurrected fossil creatures to appear around the world, though they are not as intense as in the Randall Valley and can be dealt with by ordinary means."
This can be considered a "sequel," but it also indicates that the earth's distortion has only been cured once, with a possibility of "relapse." It's not that Shard didn't handle the matter well; the earth's distortion is linked to changes in the world itself. Unless he can directly change the world and stop the "ultimate apocalypse" that has yet to reveal the right time, any plan would be futile.
