Agree, the CGI bits were definitely low points of the movie. I don’t believe that has been fixed. And if you knew the backstory (tight budget and schedule) that would help a little bit, gloss over that move.
IMO, Killing off some of beloved characters not only added gut wrenching punch to the story, it added a new dimension to Ripley (losing her child), but it set the tone for the rest of the flick. I don’t think it makes Aliens irrelevant. Life just happens that way sometimes and it’s not always pretty. We already knew what she was going to face with the Alien, but bringing in these prisoner characters good and bad, opened up new doors. Again bold and risky. I works for me.