Im betting they explain everything and it ties up all the loose ends. My bud and I were watching the trailer and we both just thought, "Why wasn't THIS story the 4th movie?" It makes logical sense that the Company was up to no good and were pulling strings all along. It also makes sense that The Company was lying to everyone, or simply was keeping knowledge of the Xenos NEED TO KNOW, and this includes not telling people like Burke, who could easily sell the information. So when Burke sent the colony to the Derelict, those IN THE KNOW, had to act fast. This has always been my take on ALIEN3, if I had to provide a concrete answer. I dont pretend to know this is a fact, just that it is illogical that the Company (or better yet THOSE IN THE COMPANY WHO KNOW) gave up on the Derelict after the Nostromo disappeared. It is not illogical to then think that they would need to get to the Colony and perform some clean up (IE make sure no one finds out about what happens on LV426) before any maines can report back and/or they lose their treasure. So..LSS there's more going on than what we see in the movies and I'd say the Company was one step ahead or right behind Ripley and the Marines the whole way. It also makes sense that the Company would want them all dead.