I still enjoyed Prometheus as it's a really gorgeous movie, stellar production design and some cool characters with great performances. I truly think the Engineer was a really interesting character, and the Dark Horse comics have certainly made some cool stories with it. So it's not all wasted.
Unfortunately, Prometheus betrays much of what made the earlier films so great. Alien, Aliens, and Alien 3 had elements of lovecraftian and cosmic horror, which is essentially about mankind coming into contact with something that's beyond their comprehension and control, and paying dearly for it. Prometheus totally went against that. Making the engineers the creators of humanity ended up weakening the other movies.
I'm still surprised that Ridley Scott had such a misread on what made the originals so good. The scene were they enter the derelict ship for the first time in Alien is soured now that they've established that the thing in the chair helped created mankind. We don't need all the answers, just enough to know that the characters are in too deep. That's really it.
I'm hoping they won't focus too much on that in this new movie. I really want them to nail it, as it'd be nice to have another solid Alien movie that people can get behind, but the rumors got me really worried that they're gonna try to tie a bow it all once again. We really don't need that.