By using a third-person omniscient narrator, Huxley is able to provide the reader with full knowledge of what is occurring at any time during the course of the novel. This knowledge is not usually available when using first-person narration and allows the reader insight into the minds and actions of many characters.
In a novel such as Brave New World, insights into the actions and thoughts of all of the key characters allows the reader to fully understand and explore the many themes of the novel.
I would not like to guess the intentions of Huxley in writing this story as a narrator or story teller without any hint of personal involvement in the story, either as a character or as a commentator. It is worthwhile noting that Huxley has not made any direct evaluative comment on any of the character or situation in the story.
I can only observe the impact this approach of Huxley has on the story. This way Huxley has managed to present the story without making his his judgment of right or wrong clear. The reader is left to make his/her own judgment of these.