This is, by its nature, a question about reader responses. I am trying to get an understanding for how readers have reacted to certain elements in Stephen R. Donaldson's fantasy writing. As such, there may not be a definitive correct answer. Donaldson was hugely popular in the late 1970s and 1980s; in Realms of Fantasy, a beautifully illustrated coffee table book about various fantasy worlds, he was described as having the greatest success of any of the various epic fantasy writers that had followed on Tolkien's heels. [The book's analysis proved to be not particularly useful, as the time of its publication (1988) corresponded to the beginning of an explosion in the mediocre but heavily read fantasy book market.]
In a couple answers on this site, I have commented sarcastically on Donaldson's apparent fascinations with philosophical puzzles that his characters have to grapple with, in addition to their evil foes. He points this out himself in the introduction to Gilden Fire, a novella that was originally intended to be part of the The Illearth War but was cut for pacing reasons and because it possibly conflicted with the main philosophical puzzle of the original Chronicles of Thomas Covenant, the Unbeliever: whether The Land was real or a figment of Covenant's imagination. In Donaldson's second series (Mordant's Need), the philosophical question is turned around; the puzzle is not whether the fantasy world is real, but whether the main character (and our universe, from whence she comes) was real or not. (I have not read Donaldson's other major series, the Gap novels; seeing hundreds of remaindered hardcover copies of Chaos and Order at Buck a Book convinced me it probably wasn't worth my time.)
My question is this: Did readers find the metaphysical questions Donaldson raised compelling? Or were they generally seen as a distraction from the story? How much of a record is there of reader response to this aspect of Donaldson's work?