Leaving the mystery of how Sherlock engineered his fake death and how far in advance he set those wheels in motion aside, there's another question that I haven't seen anybody, either here with all our great big AVS brains or in the blogosphere, address:
What was it that Sherlock had on Moriarty there at the end? I mean, Moriarty has Sherlock "dead" to rights - game over, baby. And then, all of a sudden, he realizes Sherlock has something on him that causes him to come to the conclusion that the only way to beat Sherlock is to kill himself!
WTF??! And they communicated this shared knowledge - I dunno - telepathically or something. WTFx2??!
So what was it that convinced Moriarty that the only card he had left to play was to eat a bullet? Surely that wasn't his "Plan A"...? He had a lot more malevolence to inflict on the world to just meekly bow out like that - without ever being sure
that his ultimate sacrifice would be Sherlock's ultimate demise. That's not the Jim Moriarty we've come to know and love.