Well then you have some pretty bad real life as well as video game direction. You don't need to look at your legs to know where and edge is. As stated it's fine and seems realistic enough because even I don't pay enough attantion to my legs when walking.
Not paying attention even when walking on close mountain edges? Good luck in real life

There's a saying "watch where you go".
This is not about knowing where the edge is, this is about enhancing the experience, for instance the "I'm there, very close to the edge and need to be careful"-feeling.