I don't think there is anything in RST that encourages deep nesting level or verbose markup, on the contrary with default roles it can be more compact than Markdown. If you look at good documentation examples, like The Python Standard Library documentation (https://docs.python.org/3/library/index.html), nesting is very limited and the documentation source is very clean and readable.
I agree with everything you say. All I'm saying is that in practice, the rST docs I saw, and the issues that came up around theming rST docs led me to believe that the flexibility of rST was its biggest problem (and strength).
Markdown doesn't have that problem because you can't do much with Markdown.
Ultimately, I lean towards rST since you can combat complexity with "good practices" (as a Python guy this is akin to being Pythonic) but the opposite is not true for less complex implementations.
