While I agree that FATE are far more rewarding that dungeons. I don't believe that bringing the exp/rewards up to par with FATE will fix the problem. FATE needs a nerf. I wouldn't really say this but what will bringing the dungeon exp up to par do?? Very little I'm afraid. Even then people would still run the FATE in to the ground because it's "just as good" while still being much easier. Which would still result in the "I'm 50 so I can do what I want!" mentality from those who have no idea what they're doing.
FATE, in my opinion should give you 1/4th of the reward that a dungeon does honestly. That's about how much commitment and time it takes in comparison, maybe even less.