FATES are definitely broken but they will be fixed in the future. In the meantime grab class/job with AoE and get as much cheap xp as you can. People will be bitching up a storm in the future when they nerf the hell out of FATES. Get it while it's hot seriously. Also as a poster said above if you are playing a class that isn't your highest level you get an EXP bonus. The in game text states that the farther away in levels you are from your main class the more xp you get. I've been reading online that it's 50% even when you are only 1 level away. If that's the case expect that to change in the future too. There are many factors as to why people are getting more xp this could be one of them but DD clearly gets more xp and AoE gets major xp after fate and during (xp per kill stacks greatly).