To SE:
I also don't know that I'd say it was the first example of completely new worlds. Certainly is was further apart than Narnia, which had the same animals, only in a less fallen state, and also was tied directly to religious principles. However, Conan, although supposedly a much earlier age of Earth and using many of the same peoples and cultures, at least in terms of names, I think is nearly as distant from the real Earth as Middle Earth was.
I disagree. It's not just about distance, it's about completeness. What I don't think Howard did (neither did Lewis) was worldbuild economy, culture, history, psychology, and physics. At least, not on the extent Tolkien did.
To Kije:
There's a healthy chance that if Tolkien hadn't written what he did when he did you might not have even written your heresy today, EUOL.
Well, if he hadn't written LotR, I certainly couldn't have written an essay about it. But, I think I understand what you mean. Would I, as a fantasy author, exist today if it weren't for Tolkien? I honestly can't answer. One side of me says I wouldn't--that the genre would be less popular and less viable a source of income.
However, a large part of me wonders if that wouldn't be a good thing. Fantasy might not have gotten a lot of the bad literary press that it did. There might be a small group of very creative people slowly working out what Tolkien did. And, though it might have taken longer, I think the genre would have been on stronger a footing when it finally came unto its own.
c) the same shlocky copycats would have copied whoever else came first
This is the main point I disagree with on this entire thread. By saying this, you seem to imply that what Tolkien did wasn't that great--which is very different from the other things you've said.
Tolkien didn't just get copied because he was successful. You see lot of copycats of successful works, as has been pointed out. The difference is, none of these copycats have become the STAPLE of the genre.
I don't think that whoever would have been 'first' after Tolkien would have had near the impact he did. We have the writings of those people--and none of them are as long a leap as Tolkien's work. He wasn't just good, he was AMAZINGLY better than everyone else. On a level of genius that we only see once a century, if that often. Nobody else's writing would have warped the genre like his did.
Now, to everyone (Mostly Skar and Kije):
I don't think you can dismiss the 'copycats' as easily as you have. Donaldson is no 'shlock.' He is a brilliant master of prose and characterization. LeGuin is no 'shlock.' Yet, both of their foundational series were blown off course by the all-powerful Tolkien storm. Instead of being allowed to develop naturally, they were forced to deal with an external pressure on their creativity.
The power of Tolkien's work was that even the good, original writers couldn't escape its taint.