If this can't be done because of technical reasons or cost reasons, I understand. Even one-way walls (i.e. only down) would be nice. I dunno, I just find walking into things I can't see detracts from the experience.
I hope someone on the dev team sees this. Thanks! Guild Wars really is a wonderfully enjoyable game.
Any comments?
(EDIT) I just learned that invisible walls may have been implemented to prevent players from running around mobs. If that's the case, I understand. To ask for visible representations of invisible walls (like a fence or raised rocks) would require redesigning every map in the game, so I won't ask for it.

Anyone like the idea of one-way invisible walls? You can't go up, but you can go down?