I have to agree that there is likely no possible way to unsunder the world without destroying the shards, I'm also the the opinion that unsundering itself seems to be detrimental even if the worlds and their inhabitants were left alive and themselves at the end, due to the nature of the Final Days.

When the choice is between 5-14 stable worlds of mortals less likely to have cosmic repercussions to their universe or one world of immortals that inevitably screwed themselves over (I'm of the opinion that the Sound and its effects were borne from their own creation magicks and the star's response) I'm going with the former.