A lot of really silly scripting in this
► She awakens just where those interested in the Xenomorphs happen to be ("a thousand-to-one chance"... in vastness of space... more like a billion-to-one!)
► The Alien 'situation' happens to crop up shortly after she wakes from her half-century stasis (Ripley should by a lottery ticket!)
► She flat-out refuses to accompany them on their expedition--due to veritable PTSD--then a nightmare changes her mind overnight (An acidic wet dream?)
► Her purpose there is tenuous--at most--and a patently lazy McGuffin in reality (Why would they even trust her "expertise" on 'Morphs when they weren't even alive when her claimed experiences occurred and they earlier all but mocked her about her catatonia?)
► She sees the synth, Bishop, yet does not cotton on to the fact he's an 'it', until he [conveniently] bleeds milk... despite the fact he's identical to the bot that almost killed her and just played "the knife game" a few metres away (Stasis-induced amnesia / cataracts?)
► In trying to coax the petrified "mostly" girl out from hiding, the marine grabs at her like ravenous 'Morph (Clearly not fatherly material...)
► They (and Ripley) see what's taking place there -- i.e., they're studying the 'Morphs -- yet no one finds this unusual (Ripley was obviously right about the dropped IQ's... including her own)
► Their team leader confiscates their ammunition magazines, without even inquiring as to 'why' he must do it, much less pulling his team back to at least regroup (The military must dump "The Rifleman's Creed" sometime in the future...)
► They clearly wandered into the nesting area of the 'Morphs, yet are far from perturbed; even opportunely playing with corpses to reveal a horror nostalgia moment (I know grunts are dumb, but... c'mon )
► In all their military training, nothing seemed to have been taught about luring out an enemy who's lying in ambush, nor anything about what happens when one gives away one's position with weapons fire...(!)
The first Alien film had the 'unknown' element on its side. Aliens, however, struggled with reconciling much of what its progenitor had established. Thus, is found reaching in a lot respects -- seemingly in a rush to get to its confrontations. As such, it's not to the same lofty standard as the original (albeit a decent film in and of itself), and actually makes Prometheus (and the new film's ho hum trailer) seem better (than they were / are) by comparison. It also demonstrates Scott's greatest weakness: making worthy sequels to his seminal films.