Just like Wedding, Bow is another hint on the third season of Sherlock.
Peculiar about it was the stress on pronounciation; it is not an arrow's bow, nor a gift bow but rather an actor's bow or the bow of a ship.
So, where does this lead us to?
1. His last bow - collection of stories featuring Sherlock. Possible and most probably. The directors love taking bits and pieces from different works, why not mixing all stories from that collection together?
2. Interestingly nowhere I looked so far people considered the fact that it might be a reference to Doyle's Sherlock Holmes play. Yes, Doyle wrote a play. To me, this could be a twist. And honestly: if I were to refer to it with just one word and were determined to appear mysterious, I'd choose bow as well.
While I think it's likely to be a reference to "His last bow", I wouldn't throw away idea II. Why? Because in this play Moriarty appears again. During the interview, Jim's actor was talking in present tense and reprimanded by his colleagues quite forcefully.
No proof, just evidence there that we will see more of Moriarty - either as a flashback or for real.
Probably the three hints were given in chronological order - especially since the first episode of season 3 has been revealed to be "rat". So the last one, the one where the directors promised a big cliffhanger, is "bow". If bow features Moritarty, I'd call it quite a cliffhanger, we all saw him shoot himself.
Going with this strange idea of mine: did you know that a girl once asked one of the directors not to marry off John? The answer was "I am not going to marry John Watson." ( see here ).
The playwright Doyle was working with once asked him "May I marry Holmes?" - "You may marry him, murder him, or do anything you like to him."
Far-fetched but I just couldn't resist: it's like Gatiss refering to this event - for somebody to not just answer "we'll see" or "you'll have to wait", it means that there is some meaning "indirectly conveyed". Random coincidence? Or was Gatiss reminded of that occurrence, thus adapted the wording? If it was deliberate, not up to chance, this might be a clue that the directors were having a look at the play. Playing with that notion: does that also indicate that they neither will kill off, nor marry Sherlock and John?
I love thinking through improbable ideas. Often there's a germ of truth in there.
My guess is that we will not see something from "The last bow". Too obvious. Either a case featuring a theater production or an adaption of the play.
