Really, it's the community that has progressively gone downward over the years.

Vanilla WoW was by far the best for community. You spent days in each zone going through quests and levels, and frequently grouped with others because every zone had *group quests* to complete. You formed groups for instances through communication, and common courtesy was helpful in making friends - especially if you wanted future people to group with.

Again, it's the community that's the problem.

First, it was the freebie epics handed out through BGs. Why communicate and work with people in the PvE world if you can solo berserk some BGs for purples?

Next, it was the freebie epics handed out through badges. Why bother trying to get that elusive drop when you can just grind the easiest instance for X number of badges to buy your freebie epic?

Finally, it was the dungeon finder tool. Why bother communicating at all with people on your own server when you can join a random cross-realm group, act like a total ass, and take your loot and run when you're done because you know you won't ever talk to those people again?

Blizzard killed the community of WoW with one instant gratification implementation after another.