Starcraft 2 Announced!

[alien space marine]

That's way too big a change though and directly contradicts the terran history. It's nothing to say they were being watched the entire time (it's not like the UED had any way of correcting the accident that threw those ships off course). Besides, they never really had plot holes when they added details. Even in Warcraft (no space) 3, though they gave history behind the corruption of the orcs where before it was assumed they were simply always corrupt, it didn't really directly contradict anything.

It's best not to speculate on the direction they'll take the story. We'll find out in due time.

Unless it was shown within a game to form solid canon, Its very possible that the history could be reworked since it was just written online or in a manual.

But I like the idea that their was a conspiracy and the Confederacy was secretly collaborating with earth. So all the Technological discrepancies would be solved since earth was sending correspondence with the Confederacy so allot technology believe to have been developed by the Confederacy really originated from the UED, It would explain how the UED knew so much about the Zerg and perhaps why they launched an invasion to begin with. As their subordinates in the confederacy were wiped out by a new rising power who could manipulate the Zerg Swarm.

I am sure we will learn new revelations soon enough.