Thanks for the applause and wine lol. I just love DaS.
And in 5% of cases, it actually is (the other 95% are usually the times when you wake up the next morning and ask yourself what that unintelligible gibberish is).
This seems bleak and forbidding... But it's actually not! Instead, the game is... basically gaming you. It's holding something a little bit out of reach, and then slaps your hand when you reach out for it. This forces you to go all in and just grab it instead, and you find that it is possible. And that is the crucial thing. The true value of the Dark Souls tutorial is not that it teaches you the game mechanics, because really, it doesn't, it just tells you that they are there. That doesn't mean that you know them well! Instead, the true value is that it teaches you that you can overcome the game's challenges. And you can. Pretty soon you'll be doing backflips while standing on a ledge seemingly 200 meters up, fighting some demon knight who is twice your size and who seems hellbent on having you for lunch.
And I'm absolutely positive that the same would be possible to get in an MMO. Different, but similar.
On the other hand. You are right about that shared content makes the content harder to make challenging. GW2 scales some of its content to the number of players present, but not to mention how difficult that is to get right without ending up with enemies that kill in one hit, any sort of synergy throws the scaling off. One solution would be to force players to spread out. That can be done in various ways... One way would be to have kill stealing and single looting (e.g. WoW). But sure, this detracts from the social nature of the game. Another way, seen in many old MMOs as well as in some new ones, for example EVE Online and Darkfall, is to make PvP always on. That means that you can team up, but you can also attack players at will (or with some small restrictions like not attacking party/guild/corp members). Unlike the first option, this still encourages social interaction... But it forces world PvP everywhere. And a lot of people don't want that!
EVE actually found a middle way here. It follows the "PvP always on" pattern, but it divides its universe into parts with different "security level". It's a number between 1 and 0, inclusive. In high-security space, if you attack someone, the AI-controlled space police (called CONCORD in the game) will arrive and attack you. In low-security space, though, you're on your own. Since CONCORD are very effective (you basically can't survive against them), high-sec space is basically "safe PvE" areas. Sure you can still be attacked but only by suicidal people. Low sec space is more risky, but the game keeps track of players who attack other players. If a player that ambushed others a lot enter high sec space, he'll face CONCORD ships and die. It's even possible to get such bad reputation that you become an outlaw and can "legally" be attacked at will by anyone.
But every EVE player will tell you that the most interesting areas of the game are "null sec", 0.0 security space. There, all bets are off - anyone can attack anyone without repercussions. This area of the game is more like WvW in GW2, except that it's a much larger part of the game world than WvW is.
Now that is space, but the same can be done in a fantasy-setting game. You can have cities and civilized areas where people behave civilized and only ever attacks bad guys (bandits and cave goblins and what have you). And the you can have more dangerous areas, deep forests and high mountains where the arm of the law don't reach. Such places could hold great adventure but watch your back. Well, at least word of your death will get back to the cities and villages and your murderer will eventually have to face the city guard.
And if you want limitless PvP, well, no one knows what happens in the deserts or on the high seas...
Anyway, about the centaurs and WvW style city capture and such. Yeah, it would be hell to create... What I didn't know until yesterday evening (after I wrote my last post) was that it has actually already been done! And not just in any game either. The venerable old grandfather of MMOs, Ultima Online, had a full ecosystem where for example bunnies would be eaten by wolves and if these wolves didn't find any bunnies they'd eat deer instead but then the deer population would get low and since deer was dragons' favorite food said dragons would attack human cities and villages in search for food instead. The simulation apparently ran just fine on its own, finding equilibrium points, buffer pools, dynamic cycles and whatever else that actual ecosystems have. Beautiful system.
And then they did the mistake of actually letting people play in the world. This was all still in the birth of MMOs, so the devs had no idea what to expect... Players totally swarmed the entire thing, killing anything that moved and totally eradicating the entire system.
I think that this can be made to work, but it would have to be extremely durable.
(About EVE's grind: the skill grind is something that you can literally sleep through, since your skills are trained over time even when you are logged out. The grindy part is gathering enough money to get a cooler, bigger ship. That said, though, as always, the fastest way to earn money is not to be an honest worker bee that mines things and sell them for cash. Instead, looting other players as well as playing the market are both quicker ways to make money.
And then, of course, you can start a bank. (read story #1, on page 2.) Now that is social gameplay! Sort of.)
GW2 have much greater bandwidth usage than GW1, but that means nothing to the servers vs. districts discussion...