The Willow soundtrack is transparently stolen - listen to Schumann's 3rd Symphony 1st movement. It is not just a similarity it is consciously copied. That is what is disturbing.
I have heard people say that John Williams stole this or that, but there is a HUGE difference - his main themes were completely original and totally identifiable as his own music. There is no classical composer who created Star Wars or Indiana Jones or Schindler's List or Superman melodies and then John Williams just disgusied them - those are pure John Williams and his own very original style. Even though I know - his music occasionally will stray into another composer's realm such as a section here or there that sounds like Rite of Spring, Richard STrauss, what have you. But those are sections of development, not the entire basis of the most important themes of the score. Also John Williams is a great conductor and scholar of music, and knows and loves all the great composers so cannot help being inspired by them. But the difference between that similarity and Horner's conniving, unscrupulous thievery is immense and I find it maddening when people say "Oh everybody steals..." There is no comparison.
You're right about Herrmann being not just one of the great film composers but a great composer of any form. Also Goldsmith is a unique and original composer - one instantly knows it is Goldsmith just as much as Herrmann.
by the way - another example of Horner theft that kept on jabbing at me watching Star Trek II - the "Kahn" motif. It is lifted from Prokofieff's famous film score for Eisenstein's ALexander Nevsky and keeps on returning every time Kahn appears!