Aliens are a fantastical idea though as a whole. That means Scott has complete free reign to do what he wants with the film. I know there needs to be some hold on that so it doesn't become a silly mess, however I haven't seen anything in the trailers that deems this film implausible. Although, don't get me wrong I do like my films to be grounded in reality because its easier to associate with these film and its, overall, more immersive if the films that way in clined. However, let me use the Batman franchise as example. I much prefer Tim Burtons because i find them more entertaining and visually more immersive than Nolans, not all films have to be realistic in order to be successful and engrossing.