For instance, the doc strings of all the string related functions could
have a link "For more string functions, click here" and then you're
taken to a (info?) buffer that lists all the functions in the style of
s.el's overview. That is, just function signatures and examples, no
in-depth talk at all.
(The functions could link to the "real" manual pages, of course.)
This would already be a huge improvement, given there's also a completing-read version of that page that'd act like "C-h f" but first you select a topic.
I'd like to point out that we'd get this behavior for free out of the current "C-h f" it there was aliases :-P Ok I guess I said this enough time now :-)