Maybe you could mention the scientific and technological idealistic advancements, which were extremely influential at the time both texts were developed. For example, Galvanism, which is the contraction of a muscle that is stimulated by an electric current (developed by Luigi Galvani). Shelley's understanding of all these scientific developments and ideologies are ultimately where she got the idea for
Frankenstein from. This juxtaposed with the search for humanity is obviously two contrasting issues; however, that could be a point in your essay - how science, inc. Galvanism has affected the search for humanity in our world, which then leads onto
Blade Runner and the many features of distopia seen through Scott's representation of Los Angeles in 2019. This environmental disruption (seen through aerial shots at the beginning of the film) has ultimately impacted on the way identities are formed within the film, thus impacting on society's search for humanity.
Blade Runner is ultimately based on influential events in Scott's life - his visits to Asia, New York etc. These disruptive environments (polluted, overpopulated) contribute to the way he perceived 2019 would be from a 1982 perspective. You have to remember - the 80s was a time of many advancements. Correct me if I'm wrong, but computers were becoming increasingly popular, alongside scientific advancements (cloning etc), as vocalised through the media (news programs, newspapers etc.)
Anyway, I really do hope I've helped, and sorry if I didn't communicate my view too well - I'm supposed to be doing Ancient History