The problem with fall damage is that it's difficult to gauge how dangerous a fall is until you've already gone splat a few times to get a vague idea. This is dumb because the solution to this problem already exists within the game: your stamina will drain upon taking a non-damaging fall. However, this only happens if you're in combat, as outside of combat you have infinite stamina and your stamina bar doesn't appear.
Just make falls always drain stamina and the problem is essentially solved. If the player sees that the stamina bar empties or nearly empties, then they that they were dangerously close to dying and should be wary of any higher drops.