I am talking about a full scale assault similar to Garlean attacks now, but it is massive. Takes days to fend them off(not that you have to participate or be there the whole time. just be careful out in the world) But at the end of the initial flood of garleans you get to fight a
staff controlled boss. Maybe even White raven, or that other guy in black. This guy should be way over powered so it takes the server to even try. He will have AOE's that kill level 50 alliances in 5-6 attacks. He will have a huge Huge amount of HP, but cannot heal himself. The lower levels will have a place in battle during the boss portion by keeping the garlean conjurers from getting close to him.
To keep people updated, there can be a live feed for each server focused on him, or can simply be posted on lodestone when milestones of the battle/boss fight are reached.
This is just an idea, but I would love for a server wide participation event to send this client/server out with a bang(literally the traffic could make them overheat

)
Any thoughts on an idea like this? Mine is just one example but something similar would be welcome just as well.