However, personally I think Space Marines and too much action are detrimental to a quality Alien story. I respect the opinion of people who don't think so, sure, but the idea of such a thread is to see what every member's personal take on a good AVP movie would be, right?
Well my personal take on a good AVP movie would be as hard-SF as possible, realistic, political, maybe slightly satirical to some extent (but subtly!), which mythological overtones, and definitely without Marines, and with limited action.
Which wouldn't mean no action at all - to me good action is tasteful but I envision it as a natural extension of the story's thematics and characters. Like, watch Evangelion or Madoka. See how all of the action scenes are necessary and directly answer both the characters and thematics.