Technically, levequests were supposed to be the equivalent of repeatable sidequests, are they're essentially the same thing stripped of lore and centralized to one specific NPC. Unfortunately though, the exp gained from them is rather lackluster, but I suppose that's to compensate for being able to repeat a levequest whenever you feel like.

Don't forget also that each class gets it's own set of hunts in the Hunting Log, and some can give a large amount of exp too.