I have only one criticism. The writers seemed to fall into the habit of borrowing characters from the original stories and presenting them out of context. For example, The Three Garidebs was not about 3 brothers - one of which was a killer as suggested in Sherlock's Final Problem. It was an entirely different story which can now no longer be considered for any future episodes.
Otherwise, I am a huge fan and particularly enjoyed it when they updated the original story lines.