I just watched the extras from the Bluray of season 3.
About what Moffat and Gatiss do that comes from the original:
they said 'Sherlock is not a detective show, it's a show about a detective' Fair enough, if that's the direction they want to take. Clearly the first two seasons where both but it's their show.
Moffat also said about the original 'Holmes and Watson were designed as a comedy double-act' Pardon? They can transform it into that but it wasn't designed that way! Do wathever you like with your show Moffat and it's up to me to decide if i continue with it. But don't try to distort what Doyle intended to justify your artistic choices!
The fall:
mostly quoting other people's theory that don't fit and only Benedict acknowleges that fans got a lot of individual bits right.
I wrote before, that, apart from one detail, the third theory told to Anderson was acceptable to me but that it probably wasn't the final one due to the fact that at the end Watson asks 'you are going to tell me how you did it?' and Sherlock just smile and doesn't answer.
They sort of confirm that by basicaly saying, it's either the one told to Anderson or we don't know ourselves! Very enlightning!
Also stuff about the filming mechanics but no great revelations about the questions we asked here that got no definitive solutions. Nothing about where was the underground car hidden, or how could Sholto not notice for so long he had been stabbed, or how Mary got inside Magnussen's office, or about the key or things like that. I don't include things like why Sherlock wasn't searched at Magnussen's because that's character psychology, which is subjectives. Doesn't mean we can't ask questions about that and would have been fun to hear more from them, but that's it.
I'm sure they will have more comments about things when they find the solutions themselves !