Sherlock Holmes becomes more human and more adept at fitting in with a lot of people, but he remains separate from the human race because he finds that a better place to observe that from. He stays on the mountain top because there, he can see clearly.
What is immutable about Sherlock Holmes? He favors reason over emotion, but actually underneath that, there is a lot of emotion going on. You can't suddenly make him ordinary because he would hate that. He's not suddenly going to be somebody else.
Time travel is always more magical somehow when you go into the past. Traveling into the future is something you do, every day. You're just not going to get very far. So, I rather like the past travel.
Every episode [in a TV series] is a challenge, and what's challenging in most episodes is the monster. You're always a heartbeat from the monster looking ridiculous. You really have to work so hard to make them not look like ridiculous when they turn up on the set.