The wild west setting just isn't as interesting as 1950s Americana, dystopian 1980s, or the "future". Plus the ending sucks. Doc spends his entire life warning marty about the repercussions of messing with the past... then he bangs a 20th century school teacher and builds a willy wonka style time machine train at the end. it was pretty phoned in imo. i'd still kill for one more back to the future movie but the director isn't gonna allow it so meh.