Flawed is acceptable because even Tolkien himself thought it was flawed and wanted to constantly revise things. The "flat earth" thing is the biggest example but he also was going to rewrite The Hobbit "to bring it into greater harmony with the mood, language, and geography of The Lord of the Rings.". Average is of course subject to taste but a part that stands out is a letter that referenced his "normal" sales. A figure of 100 books ordered was normal but in 1972 he was told of an order for 6,000. He might even have disliked that popularity. He really benefited from the counter-culture that might not have otherwise cemented his works as the classic we know today.
Accountancy' told me that the sales of The Hobbit were now rocketing up to hitherto unreached heights. Also a large single order for copies of The L.R. had just come in. When I did not show quite the gratified surprise expected I was gently told that a single order of 100 copies used to be pleasing (and still is for other books), but this one for The L.R. was for 6,000. -340 From a letter to Christopher Tolkien 11 July 1972