for those that manage to get every FATE is potentially powerlvling and lvling faster than they should be.and then their are those that struggle to get to a fate because by the time they get half way to the FATE, its already been completed from the mass zerg.

so the idea would be to reduce the amount of fates that spawn in any 1 area of a maximum number of 1 fate every 30 mins,make the fate mobs a lot tougher so they take longer to die,which would make the FATE last longer for other players to be able to participate in the FATE and increase the EXP the fate gives out.

every 30 minutes a fate would start,or end every 30 minutes ready for the next one,if the fate has not been completed.and wuld stop people powerlvling so fast to 50.
mobs spawn that are a lot tougher meaning more time to kill,the fate will most likely be zerged anyway the mobs would need to be fairly tough.so that should solve the zerging problem by dragging out the fate.
and more exp rewarded on completion.