Did Part III really change that much in comparison to the first movie?
I mean, they’re both period drama/comedies with time travel and a key goal of getting back to the present except the first is set in the 1950’s and the other 1880’s.
That's pretty much it. I mean, there was a love interest for Doc. But other than that, pretty much the only difference between the first and the third is the year that they are in.
I disagree. I feel Part III gave more development to both Doc and Marty (especially Doc) and focused more on their friendship than the previous two movies.