From the initial list I made (which you can see here), we need to cover three more points:
8. There is some kind of descent
9. There is some sort of "dark lord" who can only be defeated by the hero.
10. There's an absence of technology.
10. There's an absence of technology.
We'll start with #10 since it has less to do with plot than the rest of the list and, actually, almost fits alongside fantasy needing races of fantastic creatures or beings. Except that I don't think fantasy needs those creatures, I think we just like those creatures. There are plenty of fantasy stories out there that do not include elves and leprechauns. However, the technology thing is important and much more... mercurial. See, sometimes, the technology is the magic, which can make it difficult to distinguish. But let's go down the list of characters (go and see that same post for that last) and see where where and how the absence of technology applies.
1. Harry Potter -- Potter is set in the modern world, but technology doesn't really exist in the wizarding world. It was a neat trick by Rowling to set it present day but still give it that Medieval feel that everyone seems to want their fantasy to have.
2. Luke Skywalker -- The absence of technology thing may seem to not apply to a science fiction piece, BUT the idea in Star Wars, at least for the Jedi, is to eschew technology. Technology, even a technological monstrosity like the Death Star, is nothing when compared to the power of the Force. It's a hearkening back to a mystical (magical) power source. So, although there is technology in the story, the focus for the hero is to not rely on that technology but to trust his "magic."
3-5. Garion, Rand, Richard -- There is no technology.
6-8. Batman, Spider-Man, Superman -- Often in super hero stories, the technology is the magic. The best example of this (right now, anyway) is probably Iron Man, but it applies, also, to the Fantastic Four and, even, to Batman and Spider-Man. When the technology is so advanced as to, basically, not be reproduce-able for the public, it has become "magical." Alien technology is the same. And Superman is above the need for human technology.
9. the Starks -- Again, no technology.
10. Dorothy -- No tech.
11. Katniss -- Effectively, Katniss functions below technology. It's basically, a magic vs. technology environment, but the magic is the special-ness of Katniss and her superhuman skill with a bow.
12-13. Skeeve & Pug -- No tech.
14. Dresden -- The Dresden series is another one that handles technology in an interesting way. Being set in the modern world, technology exists, but there has to be some way to make the use of magic more desirable than the use of that technology, so... wizards, like Harry, disrupt technology. Destroy it, actually. What we end up with is a constant struggle between magic (the old ways) and technology (the new ways) and Harry walking the line in between the two.
The end result of all of this is a lack of technology in how it relates to the protagonists.
The other two points, the descent and the "dark lord" antagonist, have more to do with the hero story arc than fantasy specifically, but fantasy, more than any other genre, tends to depend upon the hero journey. The confusion (entanglement?) of these two things is probably what causes the association of Joseph Campbell with all of this, but the hero journey can actually be applied to any genre. Probably. I'm not actually sure about romance.
At any rate, virtually every one of our heroes has some kind of "dark lord" they have to face off against, even Dorothy. Of course, in the case of super heroes, they will, inevitably, be more than one. From my list, I'm only not sure about Skeeve (being a comedy fantasy, it's not really required and, although there are antagonists, I don't think any would qualify for the "dark lord" position) and the Starks. I don't think the Lannisters quite count as a "dark lord," and, well, The Song of Fire and Ice is not really that kind of story, anyway, but that would be telling (really, that's for another post not related to this series).
Virtually all of the listed heroes also have a descent of some type, often literal as with Luke and his descent into the cave. The descent serves as a learning experience for the protagonist. Even Dorothy has her descent (in the book) when she is made into a slave by the Wicked Witch. Again, Skeeve may be the only protagonist without a real descent in his story arc but, again, comedy!
Both Bilbo and Frodo are confronted with defeating "dark lords," though neither of them actually defeat the dark lords of their stories. Smaug is killed by Bard and Sauron by Gollum, even if it was inadvertent. However, it can be argued in both cases that the protagonists set up their defeats. Both heroes survive their descents into darkness -- Bilbo in the tunnel down to Smaug's lair and Frodo... well, most of Frodo's journey is a journey from one darkness to another -- and come out stronger on the other side.
Just as clearly, many authors have modeled these specific aspects of their own works directly after Tolkien, but is there prior precedence for these in fantasy literature?
And will I ever tell you if there is?