-Jim and Sarah get to be together for a while
-Sarah becomes Sarah again
-A new enemy appears so that they have to continue the story
It would be cool to see "old earth"/our planet in the universe too! Like Honestly when Jim and Sarah were fighting together in the Game i was like, This is so sick! I miss these days.
EDIT: I think Zeratul should be a total bad !@# for the whole LotV until he sacrifices himself because that's an honourable Protoss thing and it would be a great way for him to go out as a really honourable and cool character.
Jim and Sarah have been through too much to die honourable in my opinion, I cannot explain why it just seems right.