Them being humans in a costume is a minor disappointment for me. If they had done something mindblowing with the concept I wouldn't mind the retcon, but they didn't.
Ultimately, making the Space Jockey into man's creator makes the Alien universe smaller.
I'm not even completely sure if Engineers = Space Jockey. The Space Jockey looked like it was 20 feet tall and the Engineer looked half that, at most.