After searching for question and tags related to Sherlock Holmes, I was a little surprised to find that none really exist. I suppose this is because Sherlock Holmes is not exactly science fiction or fantasy. But then, where could I go (on Stack Exchange) to ask about the Sherlock Holmes novels and short stories?
There was apparently a Literature SE, but it failed a long time ago.
Allowing Sherlock Holmes and other mysteries might be a slippery slope towards allowing all fiction, but it seems like you're missing a huge fan base.