I was going to say that a Prometheus sequel would probably have taken it's own course further away from ALIEN, as it always seemed to me, right from early in 2011 that it was Fox who were scared about calling it an ALIEN prequel for fear of the reaction to the lack of familiar aliens. I don't believe Scott was ever that worried about it but was being advised to talk about it having the DNA and play down the connections.
However, I also think that certain reactions to Prometheus might mean that Fox will feel a sequel perhaps needs to acknowledge the familiar alien more directly, whether that's a good thing or not I don't know.
Personally, although scrutiny reveals major differences I think Prometheus is the film where the design aesthetic - aboard the Prometheus and aboard the Juggernaut, remain the most faithful to ALIEN.
The Deacon is bound to look gawky clumsy and a bit shit compared to Kane's Son, but it serves the job of closing the life cycle - at least enough to make it clear what the DNA altering goo is capable of.
The vast majority of design choices work, but there are certainly a few that were neglected in favour of easier options - the Deacon is admittedly the best example - Huante's white beast, even as an infant, might have looked as good as the original chestburter. What I don't understand is why the translucency that was so sought in ALIEN wasn't pushed further in an era when it could have been realised much more easily. A glassy version of the alien bursting out of the Engineer would have been something to see.