If anything, he's underrated
J.R.R. Tolkien, for all the love and hype he gets, does not get as much as he deserves. That might seem a strange statement to some, but I've heard, or read, many arguments stating that his writing is dry and too "prosy", his characters are flat, and while he was a great world-builder, so these folk say, "he wasn't really a very good writer".
I disagree with those arguments. I think he's one of the finest writers imaginable, let alone who has existed. His ability to conjure a fantasy at once so alien and familiar is a work of genius. I appreciate the verbose prose he used to craft his world; it immerses me in Middle Earth. I love his characters dearly, and they feel real and "true", for whatever that means.
His plots and characters owe much to the epic sagas of the Nordic peoples, and he grafts their style into the novel's style, which is why I think it sometimes appears stilted to people, but for me, this man made a new mythology, unparalleled and unmatched, which continues to set the bar for all fantasy tales to follow it, at heights which might never be reached again.