Yeah, I think you nailed it pretty much.
The great mystery is not how he faked his death, but how he survived the fall.

If he fell on something like a mattress, John couldn't have seen it but Moriarty could. Same goes for nets etc.
What in hell could he have done to make the fall look real to both of them? I already thought about something hidden underneath his shirt but I don't know if that's possible... ;)

I agree that Moriarty could have easily leaned over and looked down. But maybe Sherlock really counted on him not leaning over... He's Sherlock after all, he figures that stuff out .
Because if anyone had seen Moriarty on the rooftop the "omg he committed suicide" would have easily become a "someone pushed him!"...
I'm really not sure about this.
Maybe his plan did indeed include fooling both Moriarty and John.

Curious about other ideas on this ;)

I agree that he has to have plans, plural. But wouldn't one of them have to be "I have to jump and Moriarty is alive on the roof"? I mean, he has to prepare for all possibilities, depending on what sort of coercion Moriarty has prepared to make him kill himself. The scene with Molly proves he knew what the ending to Moriarty's story was, but not necessarily the precise path that he'd use to steer Sherlock there.

Do you think Sherlock anticipated the assassins? Or relied on being able to outsmart Moriarty? I suppose he could have, but he did make plans to jump, which means he wasn't completely confident he could beat him through anything but faking his own death.

The "surprise" was an act for Moriarty, I think, to prevent him suspecting that Sherlock made contingency plans for jumping off the roof. But you're right about stalling... he drags it out. It could be about comfort, but I'm not sure that listening to a friend's suicide note and then watching him fall to his death while you stand there helpless... talk about trauma. Think about the "if only"s you'd have in that situation, the "was there something I could have said?" doubts. I'd almost prefer not having the call at all. But then, Sherlock doesn't really understand most people's emotional reactions to things, so it could be a "not good?" moment as well. Or it could be to really sell the suicide to John, since without getting a confession from the horse's mouth I imagine he'd suspect foul play, but I don't know why that's necessary either.

The phone is really interesting, though. A recording of Moriarty talking that way would go a long way toward clearing Sherlock's name. Post-article, there is absolutely no way that "Richard Brook" could have been hired to perform that scene, so it's proof that Moriarty really existed.

One possibility would be that he, like BrightBlueEyes said, he never planned to jump when Moriarty was around.
He had a plan to survive if he really needed to jump but that was really just the last option for him.
He knew that Moriarty would want him to jump so it was safe to have a plan for that, but his actual plan probably was to get Moriarty to... I don't know, call back the snipers, make a confession, be arrested?
And he didn't expect Moriarty to spoil all this by committing suicide. That explains the surprise, which to me seems very honest.

Well, that would be one explanation. That was he only needs to fool John.
And that leaves more possibilities open... well, like nets, mattresses etc. because John couldn't see that from where he was standing.

He is very sturdy... but that goes to the idea that Sherlock and Moriarty are really the only two people as far as they are concerned. Everyone else is..beneath them? Sure Mycroft tried torturing him and such, but let's face it... how dull.

Moriarty has people he moves around and plays with. That's what they're for. Pawns in his game? Bugs in his web, as it were.

Sherlock never understood the concept, I think, that there were even other people. Thank god for his blogger ;)