I have to digress and say "nay" to that specific idea.

But a world event would be awesome. Once a month, maybe once every two weeks. "X" amount of players (50-75%) need to get "X" action done and those that actually got it done (not just partially contributed like the FATE system ranking rewards) would get whatever item, gear or Gil reward. Or one-use summon of a primal for a battle in or out of a dungeon for each player that contributed as above. Time frame would be four days, both weekend days inclusive. Can be completed earlier.

If the full required percentage of players didn't get it done, no one gets anything.

Change percentages required depending on average total completion for that world during said world events. Eg: if average of 55% only contributes two events back to back, then make it 55% to complete. Raise or lower as statistics shows. Or have same reward not won added to the next event reward for more incentive. Etc.

Bring on the world events!