Quests

Don't do a linear quest line like every mmo out there. If possible do it like the old rpgs where you have a journal and you keep track of rumors or other notes people left behind to either find a chest or certain kind of mob. There can also be quest disguised as simple favors you do for the towns people or an important member of some society. This is kind of a rant, but if the quest/favor/rumors go off in a web of quest where once you finish it you can do 2 or 3 other quest but you can only do one and depending on what you do it actually affect the npcs around you.

Also, if players don't like normal game quests, they can make quests through the public bulletin. They have to provide their own reward for the player who succeeds doing it.

There is also a place next to the arena where you can make your own dungeon, and then play it and get points for playing others' dungeons. However, you cannot change how strong the monsters are. The amount of points you get depends on how many monsters your character defeated. Also, if you die in the dungeon you do not get the penalty of losing a lantern.

Fetch quests should be for noobs, but the same npc even when in a noob area wont give a high level such a dumb quest, and actually, the person might just give you a reward in awe of your presence and in honor of you. The quest depends on what level range you are, but at the same time the higher the level range you are in the harder and longer quests get.

In quests, you won't always have to just kill monsters. Quests will test your knowledge on the in-game society, your wit, your nobility, your humility, your greed, and many things that doesn't just have to do with your character but also the person playing the character.