To add to this, one of the main reasons I think it is necessary to rationally discuss Tolkien is because far too much of the discussion of fantasy literature (and D&D) gets trapped in this never-ending cycle. Tolkien was important and influential, but there were a number of writers (some of them mostly forgotten, some of them nearly completely forgotten) that were also writing at that time who were also important and influential at that time- and to attribute everything, always, to Tolkien shows the same facile understanding of history and influence that you often see in other fields. It's like the person whose knowledge of reggae's history is that Bob Marley was wicked popular, so you literally are unable to discuss rocksteady without someone going on about everything they know about Bob Marley.
History is complicated and multi-faceted; something that I am sure Prof. Tolkien himself would acknowledge if he were still around. It is somewhat bizarre that we have to keep having these conversations about things that do little credit to Tolkien (who is still a cultural icon, even if people mispronounce his name in America) while doing such a disservice to so many other amazing people. For that matter, the idea that Tolkien did not, himself, stand on the shoulders of giants is also incorrect; it is common, albeit incorrect, for people to credit him for things that he did not do. He did not popularize the Mirkwood- this was a term that, while derived from Myrkvior, was used in England long prior to Tolkien and achieved some popularity with (wait for it) The House of the Wolflings (William Morris). Warg, for that matter, was not coined by Tolkien, but was also a term used in various sources that referred to older Scandinavian materials- see, e.g., The Old Runic Monuments of Scandinavia (from 1868), "Here we are at once on familiar ground. The WARGUS is our well-know Old-English WARG or WEARG .... WULF and and the now obsolete WARG being two words of exactly the same meaning."
It is certainly true that Tolkien had a singular genius for borrowing and synthesizing a lot of this material (not to mention his facility with language and literature!); it is also true that other authors (particularly Anderson, who spent part of his childhood in Denmark and repeatedly returned to Norse myths) also did separate, and amazing, work in disparate areas. Heck, of interest to this group is that Anderson, author of one of the most influential books on D&D, was also a founding member of the Society of Creative Anachronism.
In short, I always think it is important to remember that Tolkien has a secure legacy; it is not necessary to celebrate him by insisting that others were just imitating him. Especially when that is not the case.