Fate grinding ISN'T the exact same as EXP parties. Well, considering if they took away fates they'd likely have to make overall mobs a lot stronger on the world map. I also doubt they'd let you have 8 man parties in that instance. Likely the 4 man set up that dungeons have. You wouldn't be able to zerg AOE spam with a four man party. And, gasp, people might actually have to learn their rotations to survive enemies if they buffed them.
This is a lot of assuming on my part though.
