
Originally Posted by
Nissa
Oh, okay. It's really simple. It's hurt and control. Kerrigan, up until the Overmind's death, was the pawns of people -- the pawns of the Confederacy, then Mengsk, then the Overmind. In her "rebellious teenager" stage (that is, post infestation-pre Overmind death) Kerrigan began to really, truly have power. Since the Overmind never appeared to stop her from doing what he wanted, this is the first time Kerrigan could honestly make her own choices, damn the consequences. At the Overmind's death, she kept her power and lost the final remnant of control other entities had over her. Her fight against the cerebrates was to stop them from trying to re-create the Overmind, and her fight against Mengsk, Duke, and Zeratul was to get revenge on them for the things they did to her (she calls her actions in BW "revenge" when she forces Zer to kill the matriarch, but I kinda assumed she was letting Zer take the fall for Tassadar, since he wasn't around for her to get revenge on. Debatable, I guess). Aldaris and the UED are just people who got in her way, and she didn't have any particular grudge against them -- which is probably why she didn't let DuGalle live. She didn't get a sick kick from watching him suffer.
Kerrigan's emotions are the ultimate motivator, as shown in how she treated Zeratul. It would have been wiser of her to let Raszagal remain her brain-controlled zombie, but by revealing her trick, she hurts Zeratul. That's the only thing she accomplishes by revealing her trick early; it's not at all tactical. Likewise, leaving both Raynor and Mengsk alive can only be motivated by emotional reasons, since she apparently could have killed them when she had the chance. Thus we learn that Kerrigan's real goal is not the Overmind's (SC2 aside): she has no particular interest in universal conquest. She even gets "weary" of killing, she says. It's even possible that the things Raynor said to her had an affect.
In essence (hahaha), Kerrigan wants power so that she can determine her own life path, get revenge on anyone who ever hurt her, and make sure everyone learns that she's the big bad, and there's consequences to disrespecting her. And that's why she stopped at the end of BW. She didn't need to conquer Korhal or Shakuras. She'd basically achieved everything she wanted at that point, and owning a few more worlds wouldn't make a difference. And that's probably why Blizzard had so much trouble with her in SC2. Anyone making a sequel to BW would have to find a way to give Kerrigan new goals, or else just have other races force her into action. It's a pretty difficult spot, and I sympathize with the difficulty the writers had.