Yes. In real life you can see more than 5 feet in front of you. Keeping the fog that low only takes away from the effect.
I think the fog is great but if you expanded it a little bit (And made the build go with it.) it would be a lot more atmospheric.
You haven't been in thick fog, have you?
1) I've been in fog where you can't see five feet in front of you at night. It's scary stuff.
2) You can see the cliffs in this shot about 40 studs away.