I agree that Williams delivers what is asked for. When I'm caught up in a movie and really emotional invested, a John Williams score adds to that. My favorite piece by Williams is during the barrel sequence in Jaws. It captures the excitement onscreen and what I was feeling. And the iconic Jaws theme is an active tool in creating the suspense and dread in the movie.
But when I watch a movie and it doesn't get me emotionally invested, a strong Williams score seems out of place. It feels like there is someone behind me cheering and clapping for a movie that's just not working for me. It's a feeling I've never had for a more restrained composer like Thomas Newman.
I've never hummed a Newman melody the way I've hummed the Raiders of the Lost Ark theme or Star Wars theme when I leave the theater. There a lot of times where the Newman score doesn't consciously register to me. But on rewatch, I've noticed the music and how it complements the action on the screen. And Newman does it so well, that it's easy to overlook.
It's 2 different styles. If a Newman score is working, it's a subtle boost to the mood of the movie. If it doesn't work, I don't notice the score. If a Williams score is working, it is an unforgettable triumphant piece of work that stays with you long after the movie is over. If it doesn't work, it just makes the film seem manipulative.