Make quests repeatable.

[Ehllfhire]

Guide To Square Enix On How To Fix Leveling:

-Make the experience bonus from doing guildhests apply to every job, not just the first one you run it on
-Reward players with their choice of gold or seals at the end of a dungeon to give them incentive to run them instead of FATES
-Double experience for the first dungeon, guildhest, and primal each day
-Have grand companies sell an item you can purchase each week that wipes your current tier of hunting log for your DoW/DoM classes

Good ideas, that with repeatable quests would solve all the leveling issues.