I think the exclusion of Giger was a sacrilege on par with killing off Hicks and Newt off screen. Giger's seminal design is the linchpin around which the entire Alien series pivots. Without Giger's Alien and derelict designs, the film would have been no more than a B-movie. It's a shame about how he was treated. Giger should have been involved in every Alien movie. There's just no accounting for class in Hollywood. I bet you they dedicate Prometheus 2 to Giger.
Really looking forward to Prometheus 2 and hope that we go back to more of a Gigeresque look.