They never really mentioned much about Moriarty... assuming no body had been found on the roof, or thta they are keeping his death secret from the public then that could be why.

However is it possible that Moriarty was working with Mycroft or indeed Sherlock, they like eachother because they amuse eachtother. The only thing I didn't understand was that if Sherlock hadn't anticipated Moriarty would kill himself he would have to make his getaway fooling Moriarty into believing Sherlock was dead (sherlock knew that Moriarty wanted him dead). the Theory given as much as I like it would mean Moriarty would be able to see Sherlock had faked his death.

The main thing I can think of it s that information about Moriarty has been left so that if the writers want to they can bring him back at a later date (after all it is fiction!) but like Moffat said, they cant fake death at eachother what if they met eacother in the street?! He is dead... they have lied to us before but it also sounds pretty conclusive that he is not coming back

What are your thought?