There is a moment in this newest 3rd episode where Mary meets Sherlock at Leinster Gardens, he projects her face on the building and proceeds to tell us that he won that particular facade in a poker game, betting with his kidneys. At this point he became to me completely unrecognizable. Who is this man who lives in his mind yet goes through the trouble to set up an elaborate projection? Who is he that plays poker at such grandiose levels? (Perhaps it was an attempt at humor, something I've always appreciated about the Holmes mythos compared to your other cop and intrigue dramas, but where it succeeds most is in the smart and small moments)

Er, the projection was insurance against his leaving the building safely. And the poker game was with a criminal, so he was almost certainly undercover on a case.

Keep in mind that goddamn near everyone in Britain has read some Conan Doyle -- so the writers have to balance giving us semi-familiar plots but also adding twists to them. 3x03 did this extremely well; familiarity with the plot of the Milverton story actually makes it more difficult to predict what's going to happen.

I like the changes to Mycroft. Stories where he featured were always my favorite part of Conan Doyle's writing, and I always wanted more. Would he be more effective in the shadows? Depends on what you mean by effective. Scarier and more ominous, maybe. But he wouldn't contribute to the 95 minutes of television as well. There's only so far you can go with two actors flying solo.