Well, I'm not a detective fiction fan, but I've seen some criticisms. You can criticize Conan Doyle for a lot of things (his occultism comes to mind as being especially paining to us), but Sherlock Holmes in particular suffers from tremendous Anglocentrism and prejudices of empire (all those criticisms of Kipling's fiction? Work just fine for SH stories as well), and suffers from the mysteries being completely insoluble by the reader before Sherlock makes his absurd deductions:

'And so you see, Watson, this tuff of white hair (which I picked up behind your back and never mentioned) was sold by only one shop in the small Scottish town of Och'lag, which was open for only one hour before going bankrupt last week, from which I deduce that the crime was committed by a sailor on a tea clipper who had never been in England before or since. Wire Lestrade, there's not a moment to be lost, as I can tell by the gleam on your button from the waning moon that the tide will high in exactly 46.7 minutes!'

Compare this to other detective fiction, like The Tokyo Zodiac Murders, where the author plays it completely straight with you, does in fact give you all the information you need, and even inserts a chapter break and a message to the reader, telling him the solution is in the next chapter and if they want to figure it out for themselves, they had best stop reading right there. I didn't figure it out, unfortunately, but I had to admit on reading the solution that the author had indeed dealt fairly with me. Even something like "The Purloined Letter" is somewhat soluble by the reader compared to SH stories.