Its not the actors, the script, or even Scott. Its the "fanboys" and the internet. I long for the days before the people who dont know anything about film making could have their voice heard. I've been on this site for since the early days and the amount of garbage ideas that fuel peoples bias opinions of the recent two entities of the franchise are overwhelming. Its all bells and whistles that they confuse for good story telling. The nostalgia for the things that became their favorites parts of the originals and the undying and desire for more of the same ole stuff in every film. For most of them these ideas were formed in their minds at a young and uneducated age in regards to what make a film a good film.
People have the right to not like something, but too often they equate as grounds to say something is all around just bad. This is from their lack of ability to really analyze a movie without their own preconceived bias. Both Prometheus and Covenant are good and worthy entries into the franchise, more so than Aliens and A:R were. While Aliens changed the formula to a action driven movie, it suffers from MANY of its own problem such as turning the Alien into cannon fodder in favor of some boss battle at the end. Its comes from the low hanging fruit idea of make a sequel riddled with "more" and "bigger". Its really poor writing.
But as I said the majority of people on here saw it with a young and impressionable mind and will never see it with any other eyes, and go on to whine and complain when everything else doesn't resemble that impression.