Having said that, a beautiful example of LP in the wild is geom[0], a Clojure/Clojurescript library written entirely in org-mode. Browsing through the source, I have to keep reminding myself that I'm looking at the code and not just the documentation.
https://github.com/thi-ng/geom/blob/master/geom-core/src/mat...
This is an effect which I observed with my own literate programming attempts, too: They quickly end up with large documents that contain lots of code listings and not much explaination.
https://github.com/thi-ng/fabric/blob/master/fabric-facts/sr... https://github.com/thi-ng/geom/blob/develop/src/viz/core.org
As for the docstrings included in the core, this is largely to address complains from other users, who are used to have docs available in the REPL and I often don't have the resources/time to provide both org-mode and docstrings...
My only concern for such things is what to do with non-org loving, neigh, Emacs-hating users?
This can be generalized to all literate programming tools. I assume beyond the humble, it kills adoption.
The maintainer of Axiom did a good talk that got me into my penultimate LP kick, but this is always thing missing from such impassioned talks for it.
UPDATE: Axiom, dear 616c, not Maxima. Someone even links it in another thread to boot.