If there's an individual who can challenge Gygax in the title for Most Influential, I would argue for Tolkien.
Despite the former's apparent disdain for the latter, the author's works informed and defined fantasy roleplaying, in particular my own early games, in a way which precious few other can claim.
Yes, there are others whose names loom large in Appendix N, but in high fantasy games, at least, Tolkien reigns.
To that end, I found this supremely interesting.
Should it be used as a concrete guide for worldbuilding? Nah. But it's frakk'n neat.