Propelled by Sherlock Holmes in a fairly startling manner, the show is a one of a kind interpretation of an exemplary investigator story.
So, there's no substantial response - yet. I have contacted the BBC for additional remark however, and will refresh this page when I hear back.
Show maker Steve Moffat appears to concur, as well. Addressing Radio Times, Moffat said he wouldn't preclude a side project or spin-off right now."The story will end in four episodes. It's finished toward the finish of that," he made sense of.