We shold find out who killed the engineers.

I think Ridley should answer this question in the next film. Who really killed the engineers? If so, why did they. I think we have a huge potential of reintroducing the Predators to perfectly coexist with the alien and Prometheus universe. Remember back in AVPR, the predator was peeling the skin on a skull, and surrounding him was a trophy case. And if you look closely, we can see a space jockey helmet. We could do a plot where the Predators actually came to the engineer's LV-426 base, as the predators were trying to stop the Engineers from their evil doings. Or just killing them because for their trophy, or because they had conflicts with each other in the past. What would be cool though is that we could see Shaw and David could be caught up in the battle between the Wolf Predator and an Engineer. And of course the Predator's going to be taller and they should make them look more badass. Whatcha guys think.