I see lots of people bitch about the quests and I think its a valid complaint. What I don't ever see is anyone offering a suggestion to replace it. I'm sure no one wants to go back to forming a group and killing the same static 5 spawns over and over and over for 3 hours.
As for my suggestion, I think it might be nice to tie quests to zones. GW2 had kind of a good idea with events but their events frankly sucked. There should be a way for the zone to be constantly in a state of war with npcs from both sides pushing at various times with well defined ways to push the enemy back and make the enemy push. This way the zone is never dead, an issue in GW2, but instead stays alive and regardless if there are 100 people in the zone or 1 you should be able to accomplish the goal. Mob xp should also be significant. All loot should be significant.
In addition I'd like there to be an option to simply pharm stuff for level. Insert generic quest, make it repeatable but let me just gather tons of the items and turn them in once. Those centaur that gang banged the guys daughter should all die, not just 10 of them and move on. Collect 100 scalps and move on to the bears, collect 100 livers and turn them all in for 2 or 3 levels. I know that most people don't enjoy that type of game play but sometimes you just want to pharm some stuff and its nice to actually be rewarded for it.
I'd like to see both those options done right in a game which encourages grouping, makes all loot meaningful, has a strong player crafted economy and faction / open pvp with territory control.