People grossly underestimate dungeon exp compared to FATEs. 100k exp per run in the mid 40's, nearly an entire level at 20. Hardly what I would call "laughable". If even one person in your party is new to the dungeon, everyone gets a bonus at the end. I think people just do FATEs because its mindless and requires no more thought then checking a map and following the herd. If you hate waiting for DF, queue up and change to a crafting or gathering job, or do FATEs solo, or do hunting log.

I don't know how people even tolerate FATE grinding, can't imagine a more boring thing to do in this game outside of shard farming.