I had the idea for an endgame open-world zone which incorporated many of these changes too (dailies too).

Dynamic mission or time-locked chambers/paths which hold outerworld bosses or provide special access to new, intense timeworn map locations.

FATE's could be huge here with enemy assaults/sieges taking place... have skirmishes/wars break out all around. Even scripted FATE sequences that are chained together...

One group needs to handle the brunt of the enemy force tearing through the front, whilst another needs to hold back the flank, etc. Depending on the success/failure that would turn the tide of ensuing events, ultimately altering the overall outcome.

Get crafters/gatherers involved too, bringing up supplies or building/repairing various war machines.

Different battalions waving the flag of their respective Grand Company, etc. Could be tons of fun.

Grander scale events could be biweekly or something, with smaller operations always ongoing.