I hear you; obscuring the identity of a villain does indicate it's someone known.

One point for the series is, I guess, that there really aren't that many options for the Faceless Man, because there are so few White dudes who matter. If the FM isn't Nightingale himself, the FM's identity basically has no plot relevance (the other White dudes are either too old, like Peter's father, too big, like Seawoll, or have no real meaning so far, like Caffrey, whose name I literally had to look up).