Good stuff. When I wrote an eBook I found the extra features of reStructuredText to be useful (index, glossary, graphviz & Tikz environments, etc.) and wrote a sort of similar post.
Yeah the rSt markup is pretty idiosyncratic and both anal-retentive and a bit inconsistent (e.g. it can be hard to internalise where it does or does not want blank lines) but Sphinx is an actual document system, having to work with markdown for anything beyond a single file quickly gets painful.