I re-read most of the stories a few years ago. It's shocking/surprising/depressing just how many things repeat themselves. From the obvious, veteran of Afghanistan war in the form of Dr. Watson, to London being a melting pot of so many cultures, with high society reigning from ... on high.
I also agree that the view directly into the state of mind of both Watson and Holmes was refreshing.
Realising current day events rhyme very closely with historical events is pretty eye opening.
It’s a tragedy of the commons we are all largely oblivious as a species.
It's notable that the BBC recent adaptation set in the present day was also able to make Watson an Afghanistan veteran.
I read the stories as an child, and seen various of the film adaptations; Holmes became a meme even within Conan Doyle's lifetime, but I'm sure I'd benefit from going back to the source as an adult.