I felt this score was much more percussive than melodic. Much more so than the previous films. That was the first thing that struck me when skimming through the soundtrack the day before I saw the movie (didn’t want to hear too much, but couldn’t help myself). I don’t mean that there were more drums (although there were, I think), but that the other instruments also focused more on staccato rhythm.
Compare something like the asteroid chase in ESB to the Falcon chase in this and you can definitely hear the difference in approach. That’s probably why a lot of people thought it was less than stellar. Personally speaking, I also thought it was a bit of a let down, but I didn’t care all that much. It wasn’t an issue of the music being bad or uninspired, just that it’s hard to top the first two SW movies.
I do think on some of the action cues (particularly The Falcon) the music is more rhythmic than melodic. If I were to guess, this is just a sign of the times. Now that you can edit films on a computer, last minute nips and tucks are much more common, so Williams has composed music that can be more easily edited.
Most modern action scores are more rhythmic than melodic for this reason I think.