You can talk about leveling curve, difficulty, itemization, lore, and ingenuity in the MMO space until you are blue in the face but there are only a few areas EQ next would need to be savvy about to bring back what EQ had going for it:
1) Class interdependence, ditch the hero nonsense and let people play a certain role
2) Keep instancing to a bare minimum
3) Keep mob leashing to a bare minimum
These items are what made the memories and playback value of EQ what it was. It let people interact, depend on, and loathe one another to a degree that is lacking in most other games. Especially on PvP servers these constructs allowed the game to live up its "massive multiplayer onlineroleplaying game" title. The coddling used in today's games by developers takes players away from having a genuine role in how things play out.
Nostalgia and rose tinted arguments have their place, also serendipity, masochism, and sadism likely had their place in making EQ what it was. You would certainly be correct to malign the original EQ, however it did a number of things right, and while understandable it is unfortunate other games are too timid to make a true MMORolePG for investment reasons. Though I certainly think a case can be made, and eventually will be, a high fantasy game can still be successful without shoving a pacifier down our throats.