ISSUE
New world is a game that is hyped for being completely open world. Yet the main event in the game which is WAR is a piece of instanced content. Holding the keeps in the open world seems to be an uncooked feature for the lack of incentive and effort required or is trivial and a cakewalk if there is no other blob of enemy players trying to do the same. Also there might as well be two factions as there are no 3-way battles.
SOLUTION
Whichever faction has the hold of the fort when a war starts gets bonuses.
If the fort holding faction loses they get to keep their fort bonuses for one day even though they lost. If they win they get double bonuses from the keep for one day.
If it is a third faction that holds the keep they will get the losing bonus immediately.
Siege weapons that can be built on the spot are required (catapults, cannons, trebuchets, etc) to destroy the defenses of the keep to capture it. ( It will also add another sink for materials and possibly gold + keep repair requiring resources)
This gives a lot of “epicness effect” to the game. Lets people that did not get picked for the war to participate in something exciting without hoping to get picked for the war. And possibly gives a glimpse of whats to come to unsuspiciously wandering new players finding themselves in the middle of a three-sided epic scale battle.
COUNTERARGUMENT
A whole server of players concentrated in one area could be problematic.
NOTES
It is not a simple feat and requires a lot of development i would presume but hey! They did make the game so what is an update next to years of developing from scratch.