Opinions on the world building?

What are your thoughts on the world building of the original Filmation He-Man and She-Ra shows? I know they've been said to be influenced by Lord of the Rings, Conan, Star Wars, Dune, even Jack Kirby's Fourth World, but as its own thing do you think the makers of this universe did a good job? Would you consider Eternia/Etheria to be as expansive as say Middle-Earth in terms of scope and diversity of characters/races?