I find Howard Shore's action music in LotR a lot better paced and placed than Williams late action music. I just find that Shore is perfect in placing the right notes at the right time, so consequently I find his music more thoroughly composed; if not in numbers, then certainly emotionally and in terms of how a musical arc is established. A piece like The Siege Of Gondor, particulary the beginning (Ash And Smoke on the OST), may, purely compositionally, not be on par with Williams' complexity, and yet, how it builds, how it is conceived as a piece of dramatic music and how it is placed in the film, it is vastly superior to the last ten years of John Williams action music.