I think CT can tend to be a little bit too self-critical regarding his own input into the whole Middle-Earth thing. It's well documented, but easy enough to forget, that his status at one point was the Principal Collaborator (a glance at any of the letters from the early 1940s will reveal this), and that his work helped shape the Middle-Earth we know and love. It's easy enough to see things that one would have done differently or better with hindsight, but sure ain't we all guilty of that to an extent?