Welp... I think another reason is because... they created an exp monster.

I managed to get the Event done for 3 more of my alts, so 5/8 characters done with event.

On the last character I ran through it today, my instance began dying after the final FATE in the string of 5. I entered during the Marlboro fight though, so I needed to clear one more FATE to got to 100 tokens. However, the Garlean FATE was supercharged when it spawned and we were not able to complete during the 10 minute timer. I ended up getting Gold Rating on a Failed FATE, which awarded me 10 tokens... so I was still short by 10 to 100. Marlboro Spawned right after, and my instance now had less than 20 ppl in it. I ran over to hold the adds, and ended up dying cuz no one was healing me. Ended up dying, but rest of players pulled the Marlboro back from the adds. I released, ran back, and it was dead... in less than a minute. Fortunately I was in a light party and I did tag the Marlboro at the beginning, so I was awarded Silver credit and 10 tokens.

So... confirmation that the difficulty of the FATES does scale... and since they trigger continually based on when the previous FATE is defeated... In theory, the exp gains for 51-60 in a low pop instance could be rather ridiculous...