I loved the movie and the themes that Ridley & Co. wanted to explore really resonated with me. It's interesting, and I don't want to paint with too broad a brush here, but for those who were very interested in the Space Jockey from the original Alien, most of the disappointment re: the engineers seem to be people who were invested in the Space Jockey concept early on. For me, the Space Jockey (I didn't even know it was called that until very recently) was just a point of curiosity. Something neat, for sure, but didn't inspire me to wonder about its origin. I figured it was a creature that used the Alien (Xenomorph) as a weapon. Prometheus did nothing to really dispel that for me. It did not take the alien out of Alien for me. But I can understand for others YMMV.