I was mulling this over and think I had a minor epiphany.....well; it's actually coalescence....
A lot of people (especially me) talk about "dumbed down" games which lead you by the nose through content, with very linear progression and quest paths. The opposite is "open world games" where you are not required to follow a specific "linear" path for progression.
There is a subtle, but crucial, nuance to this. Frankly I think it's the point that most of today's game developers are missing.
Game developers today will claim "our game has many parallel quests and you can XP without having to quest so it is non-linear". But that's not the point. They THINK it’s the point but it’s not.
Those "other" games truly do have a large number of opportunities via xp-ing and questing so players can have a myriad of different experiences. One player might pursue Quest-A then Quest-B, while another play chases quest-P, then quest-Q. And those developers think that is an "open world". It is not really an open world. Even if you give players a thousand quests to choose from, that's not an open world, it’s just an overlap of a thousand linear paths. It doesn't even feel "open".
The "magic" that Everquest had was that there weren't always such things. There were situations in the world and the player-base had to figure out how to solve it. I don't mean solve the puzzle of a quest, I mean the players had to invent/concoct/create solutions that the Devs never imagined. The Devs created the world and turned the players loose on it. The players then came up with the way to succeed and it wasn't just figuring out some quest the Devs already had designed. That's the mistake.
Other games have the Devs make up lots of "paths" for the players and the players bounce around until the figure out the Devs puzzle, which wasn't ever unsolved. It was just hidden from ther player.
If that's all there is then you lose the real feeling of openness. You have, instead a ton of solved puzzles looking to be solved. Everything is solvable. Everything was designed to be solvable. You need a sprinkling of something more, that will make or break the flavor of the world.
In Everquest, there was a sprinkling of totally unsovable situations. There was a sprinkling of completely dead-ended things without any reason or known backstory. And, there were situations that the PLAYERS had to solve. Not that the Devs already knew the solution but that the players had to figure something out and even the Devs didn't know how it would get done.
*THIS* is what makes an open world truly open and "real". The players create the solutions - they don't just "find" a hidden solution.
For example, the Sleeper was never supposed to be awakened. Players figured out some way to do it. There was no designed way it should be done.
Look at things like pet-walling. OK pet-walling sucks but its a solution the Devs never imagined and the players created it with the tools they had.
Look at things like pet-pulling. Remember that? Again, it was not something the Devs ever imagined.
Look at zoneline trains, swarm-kiting, etcetera.
Look at multi-questing - that was not intended but it totally changed questing in Norrath.
Heck, look at trading items - you want to hand an item to your alt? Find a safe place, drop it on the ground, log out, swap toons and pick up the item. Devs never saw that one coming. But it was a "situation" players needed to solve so they figured something out.
That challenge and ability for the players to simply use their heads to take whatever whacky tools they have and build a solution to a situation is another thing that made EQ magical. And a lot of that was totally unintended. All the games that have come since have tried to design in solutions for everything so players don't actually "build" their own solutions - they just "find" known solutions.