I hate to say it but I think these new alien movies (prometheus/covenant) are far more meaningful than the action packed extravaganza of Aliens and the depression of Alien 3 - Scott seems to have a plan - my guess is that David, aside from being the ultimate creator of the Xenomorph, will ultimately control the evil Wayland-Yutani corporation - and that this storyline will confront the questions it's posed. - I also think the Engineers might have created humanity as part of their war (they were manufacturing those weapons for a reason, right?) to be hosts for their bio-weapons.....