It's almost impossible to replicate this in today's MMO's because the environment in which they exist has changed so fundamentally. This sort of information is compiled, collated, and made readily available at such a rapid rate that unless you're involved in beta testing or push yourself at a breakneck pace after release to stay ahead of the information curve (and thereby undercutting your ability invest time into exploration) it really is hard to experience newer games on this level with any sort of consistency. Sure you can consciously avoid spoiler information outside the game, but it still takes that special luster off of finding some obscure, out of the way cave or NPC and upon telling a friend or guild mate about it immediately hearing "Oh yeah, I saw that on YouTube a few weeks ago" instead of delving into a discussion about the various possibilities connected to the discovery.
Those of us who got to experience the genre in it's infancy and enjoyed this particular aspect, whether it was in UO, EQ, AC, or any of the remaining handful of titles that came out in those first few years, got to enjoy something special (to us at least) that players today just aren't capable of knowing on the same level and to the same extent that we did, even when they are themselves introduced to the genre for the first time. Unfortunately, we aren't able to get that experience back either, but at least we can take comfort in that we were around when it could still be had.