I think it would be great add a mechanic to jumping where the survivor reaches out his arms in front of him to grab onto a ledge.During a discussion between me and my friend we imagined "Not any average Joe would be running across rooftops, the risk would be too high" envisioning "How many people would actually take that risk, of breaking their legs or worse, so the few who do take the risk will be on another level of survival." This could result in an ability that is not gained through game experience points but earned through passed knowledge and trial and error, like real life. I envision a random death scenes with no obvious cause of death, and an eerily un-looted body.