I wouldn't want to see a zone like that. See, the thing is, while generally I do like challenges, in mmos there's an expectation that you're going to be traveling back and forth around a zone over and over again. Adding things that make a zone a pain to traverse like traps or dangerous mobs doesn't really add a fun challenge. It adds frustration, which is why it baffles me that people keep asking for stuff like this so much. Sure, it might be a good time your first time through the zone, but what about your second? Or your third? Or your fourth? Or your hundredth? This is actually what drove me away from guild wars 2.

In GW2, there was an (at the time) end game zone called Orr. That zone was densely packed with mobs, and just about every single trash mob had some form of CC they could use on you, whether it was a paralyze, or, even worse, a grappling hook. It made the zone "dangerous" sure. If you weren't paying attention it was totally possible to get mobbed to death, but there was nothing fun about that. It just meant that I'd have to waste my time running back through the zone again. That sort of challenge without a purpose adds nothing. That by contrast is what makes eureka work.

Exploring eureka is challenging (at lower levels anyways) but you do get something out of it that makes the challenge worthwhile, and once you're done, you don't have to go back so you don't run as much of a risk of getting tired of the place.