In so many art forms, it's almost more sensible to evolve than it is to churn out more of the same, even if it is brilliant. That's why the Beatles, David Bowie and Radiohead are so idolised; true genius shines through whichever mask you wear. Sherlock also needed to change. It would have been frightfully easy for Moffat and co to readapt another three Conan-Doyle crime-scenes, scare the pants off their viewers, and return to the strange relationship that was "Johnlock". They moved that relationship on though; both characters realise now just how much they need each other. They made the show funnier: it's still tense at times, but it rewards the incredible talent that Freeman and Cumberbatch have for comedy. But most importantly of all, it doesn't focus on being a Conan-Doyle remake, it just centres on being the show that Moffat and Gatiss have built. These are fully-formed characters that don't feel like adaptations anymore, and Series 3 treats them as such; it gives the limelight to these actors' performances, not the retold detective stories.
