Blizzard has posted a short Q&A, answered by Brian Kindregan, co-lead writer for StarCraft II, which answers some of the questions collected by Blizzard over the months. This Q&A only has two questions answered, both of which can be read below.
Question: How did the Terrans enjoy such rapid population growth and colonization of the Koprulu sector when all they had to work with were four broken-down ships? According to the lore, four ships containing 40,000 humans crash-landed and established three colonies in 2259.The events of StarCraft 1 occur in ~2500.Yet it seems like the Confederacy/Dominion are full empires with many worlds and billions of residents. For instance, Tarsonis had at least two billion. No matter how I figure survival and reproduction rates, I just can't see how it makes sense.
Answer: This is an excellent question, and one that has been discussed internally for several years. I've always said that these were four crashed colony ships. So while much of their technology was lost, there were certainly means to ensure a foothold on a new, hostile planet – frozen embryos, frozen fertilized eggs, certainly extensive cloning. There were also methods of boosting food production to support explosive population growth. Mmm, tasty nutrient paste! One tablespoon does you for the whole day!
Because this tech was harnessed by survivors who only had a fraction of their intended equipment, it was lost 50 or so years after planetfall. But that was enough to swell the starting figures quite a bit. Let's suppose those starting figures get us up to 400,000 within 30 years of crashing. (Ambitious, I know, but a civilization that can build massive interstellar ships could certainly create such tech.) We should assume that for the first five or six generations, there was enormous social pressure (if not legal) on all fertile adults to spawn as many offspring as possible. Families of ten or more children. By the third or so generation, infant mortality rates might have risen a bit as the old tech broke down, but they would have dropped again as the colonists rebuilt their technological infrastructure. Now the numbers start to make sense.
Question: In StarCraft, the Queen of Blades told Mengsk that she isn't interested in revenge. Why is killing him suddenly her life's purpose, according to the most recent trailer?
Answer: The Queen of Blades and Sarah Kerrigan are not quite the same person. The Queen of Blades is essentially Sarah Kerrigan under the influence of some devastating forces: incredible power, a dominating level of psi energy, and the presence of Zerg mutagen from the cellular level up.
To be clear, the Queen of Blades is not a separate entity that possessed Kerrigan. Kerrigan is (certainly in her mind) responsible for the terrible things she's done. She has immense guilt for those actions, but she was not completely in her "right mind" in Brood War.
All of that is a roundabout way of saying the Queen of Blades felt no need to kill Mengsk. She did not see him as a threat. Sarah Kerrigan, on the other hand, knows that Mengsk wants her dead, and she very much holds a grudge for his abandoning her on Tarsonis.
Battle.net - StarCraft II Creative Development Q&A: Part 1