[Dox]

I think it's almost guaranteed that Kerrigan will sacrifice herself "for the greater good" in Legacy of the Void. She really doesn't have much going for her now that she has:
1) Thrown away her humanity
2) Lost Jim
3) Got her revenge
4) Arranged a successor to the Swarm

One might argue why she can't just use The Artifact to bug zap her back into a Terran again; leaving the Swarm to Zagara. I'm sure this could be explained any number of ways. ie. The "Primal" transformation on Zerus is irreversible, unlike the first time around where Abathur wrapped her in a chrysalis and modified her cell structure. Or more importantly, she knows Amon is out there. She knows this is the biggest and most dangerous threat in the universe, and she needs all the firepower she can get. She needs her crazy Zerg powers. She needs the swarm. The only part that doesn't really make sense is, "Why does she care?" It's somehow out of character for the Queen of Blades to go crusading against the big bad unknown, although I guess Sarah Kerrigan's sense of morality (and Maiev-esque lack of purpose) can justify it. Either way, her role in the story has wrapped up. She's killed millions, and it's time to pay the price. She's first in line for martyrdom. With Sarah gone, and the universe in a happy place, I wouldn't be surprised to see Jim kick it at the end either. On the flipside, he is the poster boy for SC2, and there has to be SOMEONE left standing at the end. They sure as hell won't be killing Zeratul in his own game.

The only other part to keep in mind with the conclusion is that Blizzard traditionally does NOT do happy endings. Whether it's WarCraft, StarCraft or Diablo, things often end up going south before the credits start to roll. Diablo 3 has been the only exception to date, although with Adria still at large, it's not all quite sunshine and rainbows in New Tristram yet.