One thing to think of in how Sherlock managed to survive is that whilst he might have done something clever to fool Watson who was watching from below, that wouldn't necessarily fool everyone who saw him apparently jump off. Weren't there still assassins watching him? And maybe Moriarty had other people as well, plus there might well have been other people in the street.
So if Sherlock wanted to be thought dead by everyone with no evidence that he'd actually survived, then his plan would have to work without the possibility of anyone seeing how he'd done it. Maybe he could have kept out of view enough on that rooftop to do whatever he did, but surely if anyone had a suspicion that he'd faked it then the papers might well get onto it, meaning that his enemies may suspect that he was alive after all. But then I suppose that if the paper's did think he was dead then he must have been successful however he did it.