So we know from RoW that even a spren as powerful as the Sibling can be corrupted given enough voidlight, essentially making it an Unmade.
Following that, I belive there should be a way to Remade an Unmade with stormlight (or lifelight, I'm not picky). And I think it's quite obvius that's what Sja-anat will do, to free herself from Odium's influence. Or maybe not, 'cause the Sibling also said that being Unmade is the same as death.
Aanyway, my own haedcannon until next book release is that Sja-anat will become a warlight Bondsmith spren (same as the Sibling is a towerlight spren), and I have two perfectly good and circunstancial proofs:
Rlain said he could hear the Rythm of War from Tumi.
Sja-anat's name is derived from a Semitic war goddess (according to coppermind wiki). So war goddess -> warlight spren. Irrefutable evidence.
Thank you for listening my madman speech.
Have a good day.