If it worked for Empire Strikes Back and Revenge of the Sith with their comparatively darker moods, I see no reason it wouldn’t work for The Last Jedi. I’ll go so far as to say having to change the music to fit a darker mood is a lazy way out in creating that mood.
Nope, in cinema you establish the mood through music. The tone and music should go hand-in-hand. It’s not a lazy technique and has existed since sound was used on films. Having a music that is in opposition with the mood of the picture will feel out of place. It will become more like an opera and less like cerebral cinema, which I think ‘Star Wars’ also has the capacity to be.
Again I say, do not mean to disrespect anyone here. Just sharing my opinion as a cinema lover.