Re: completism - I'm glad I only read the compilation that I did. If the guy was that formulaic his table scraps and lesser stories strike me as not really worth bothering with. TonyV remarked at the time I reviewed Tales that "one reads Lovecraft for the quick hit--"The Rats In The Walls" and suchlike," and that 800 pages of Lovecraft in a row is a terrible idea by any stretch.
I really like God Emperor. Leto II as a half-sandworm 1500 year (I think it was) after Children Of Dune is certainly an interesting start for a new Dune chapter. And I don't remember the book being plagued with talkiness.
All I know about August Derleth is that he gave different coordinates for the location of R'lyeh than Lovecraft did.
I thought the 60s did a lot to improve Lovecraft's popularity? Or am I mistaking him with Tolkien?