iDeduce
Well Sherlock did pick the place he'd jump from. Or that's what you said before hand. I missed that part were he picked the place. With the refitting of the hospital there would things in the way a lot of things, the best bet would be the front were he'd jump. However he covered that base with the garage. In fact in that spot were he first looks down you can see chalk outlined. As if he went there and showed his irregulars what to do.
Moriarty does say "unless my people see you jump" to Sherlock, so I'm assuming John is not accounted for in Moriarty's plans to be at the scene, thus why I'd believe the snipers have their eye on Sherlock specifically and not waiting around for John's reactions.
IDK there are a lot of holes however any one of us theorize how he dies. ;D
There was another guy on youtube who gave some more good info about a soft landing.
Why do people think Sherlock's body on the ground is a fake/imitation? I'd think a fresh dead body like the one John touched would be stiff with rigor mortis, and if it isn't it'd be like 3+ days old and smell like s**t.