Berin Kinsman of Dancing Lights Press has written an extensive post that is relevant to one of the perennial debates of Appendix N discussion: does the Earthsea Trilogy belong on the list or not…? He points out that the setting “does not neatly map to any real-world places of history” and that though it “borrows Tolkien’s tone”, the series does not “tap into the same mythologies and analogies”. While that has been the dominant approach to fantasy since the late seventies, I doubt too many fans of pulp fantasy could get too excited about that approach. Those factors are exactly what typifies the watered down mass market fantasy that has flooded the market in the wake of successful novels like Sword of Shannara. And though balrogs and goblinoids might have been lifted wholesale from Tolkien’s works, very little of his tone was extant in early D&D.
Le Guin’s oeuvre contrasts greatly with pulp writers like Edgar Rice Burroughs, A. Merritt, and Leigh Brackett. Earthsea’s “magic is often small in scale”, good and evil there are defined in terms of an Taoist sense of “balance”, and “the action in the books in minimal”, but Beren nevertheless sees something that can help game masters running tabletop fantasy role-playing games:
Le Guin’s fantasy is far more philosophical, driven by story and character. If you want to read the Earthsea books as inspiration for a game, it cannot be on a “game mechanics” or “encounter design” level. You should approach it by considering that character actions have ramifications within the setting, for better or for worse, and the additional story thread that get generated not only by whether they succeed or fail but in the manner in which they attain those successes or suffer those failures. You need to be able to think in terms of balance, of ecosystems, of politics and economics and culture. You need to think beyond the encounter, beyond the adventure, and consider the impact that the characters have on the people they meet and the places they journey through. Thinking on that scale, I believe, has made me a better gamemaster over time.
In other words, with the exception of a few pulpy scenes that are not representative of the series as a whole, Earthsea is primarily going to be a resource for developing the high level world-building aspects of your campaign. Of course, as any seasoned game master can tell you, that sort of thing is not particularly relevant to getting an old style D&D game off the ground.
Perhaps D&D was destined to evolve far beyond the possibilities of an off-kilter fusion of Vance and Leiber and Moorcock turned loose in a strange blend of science fantasy and the Medieval. But going by Berin Kinsman’s analysis here, I think it’s pretty clear that very little of Earthsea’s approach to fantasy is in evidence in the earliest editions of D&D. Even if the compilers of 5th edition saw to it to amend the venerable book list by incorporating it into their iteration of Appendix N, it’s clear that its omission from the original was neither an accident nor an oversight.