I'd like the invisible walls removed. If I wanna run over the edge, I wanna run over the edge and fly into my cyberdeath. Also fall-damage. Yes. I'd absolutely would love jumping down somewhere and having that Ohhh shieeeet- moment and the feeling of regret, while flailing like a stone before my certain destruction.

Also, to your idea above - sounds pretty neat actually. Maybe also make some more "hard" to find and gimme a achievement and a title for actually finding that NPC.
Actually, on that matter - I wish they would steal some stuff from WoW. Getting the weirdest achievements there was actually pretty fun to do.