The barrow wights and old man willow are kind of cool.

And Bombadil’s old forest, with a testy but not ultimately evil Willow tree is the heart of Tolkien’s vision of English wilderness - not tamed but not horrific either. The movie does a bit of violence to the complexities of the world - reducing the snow in Caradhras from an independent agent hostile to human affairs to Saruman, and removing the non-Sauron hostility of Old Man Willow. In Tolkien’s world, humans are not the sole or primary story, it involves ancient entities with differing interests woven into the fabric of existence, which we participate in but the story is larger than us.