I don’t think it’s fair to compare the first and second drafts of Star Wars in 1974/1975 to the first and second drafts of Star Wars in 2015/2016. Not only because there was a lot more freedom and time for Lucas to work with back then, but because the way movies were made and the pipeline productions were put through is vastly different.
This DOTF draft would (and did) change from its initial draft to the one that ultimately caused Kennedy to get Jack Thorne to write something in a last ditch hope to get something Trevorrow could direct. But George Lucas isn’t JJ Abrams, and JJ Abrams isn’t Colin Trevorrow, and to really get an idea as to how different the story probably would have wound up, it’s not a good call to look at the now-legendary transformation Lucas had literal YEARS to make with Star Wars. You should probably look more at productions like Star Trek Into Darkness or Jurassic World. Or The Force Awakens, honestly. I don’t know if we know exactly how different that first draft looked compared to what the shooting script looked like, but I get the sense they were about 70% the same, roughly.
The simple fact that time was short and a release date was locked before the script was even finished makes comparing the two developments almost impossible. There’s only so much you CAN change from your first draft when you’ve got about 18mo to make the movie. Lucas’ first draft changed on the way to the fourth because he had something like 2 years to develop it before he even started pre-production, and he had a ton of friends pitching ideas over the course of those two years. There’s a level of patience, collaboration, and studio freedom that basically doesn’t have a parallel here in 2020.