Like the title says.
It will:
1.) Reward the people 'in the know' of the feature thus adding to the obtainable skill-set, rewarding with slightly better mobility around the map.
2.) Add to realism. When you fall from places, you better watch where you are landing, especially with heavy gear.
3.) Punish 'arcady' situational awareness. Intel saves lives, especially when one is trying to be mobile. Dropping from the second story while at the same time getting a satellite-view of the entire area from a high place is a bit too far and too beneficial.
Problems:
People could look around and then look down at the last moment. Must check that the player was looking down at least 70% of the fall.
Overall fall damage may need to be adjusted.
Justification: Especially with heavy weight I already find myself looking straight down to make sure I'm not falling from too high a place and this seems like an authentic, reasonable behavior that deserves an incentive.