Tom is very much a character that really only works in book medium. You can take time on a character that only raises questions in a book, but on screen you are limited in only showing characters that NEED to be there.
Tom builds the extended world at large while not really answering any immediate questions. He has no impact on the story itself of the Lord of the rings, which is why he's such a divisive character. He serves zero narrative purpose. The hobbits could have gotten the barrow blades several different ways which is the most obvious thing he does for the story. The blades have zero connection to Tom outside of him being the catalyst for the hobbits getting them.
Tom represents a few different ideas that work for the larger narrative, but has no business being in movie or TV form.