It'd be nice for things like elevated terrain or cliffs. If I'm on top of a cliff I should be able to see the bottom and around it. If I am at the bottom of a cliff I should not be able to see over it. If there is already a way to do this pleeeeeeeease let me know.
Here is a popular Suggestion thread for that. Add your Comments and Vote +1 if you agree it is a match, Dynamic Lighting - One Sided Dynamic Lighting