WAR/NIN was always there. Until Ridills, better merits, and adaberks became more readily available/obtained at large, it became a trend. Oh yeah, making stuff like speed belt and the like more available helped too. Again, context.
I'm just gonna quote this war/nin became the flavor of the month when they added ACC food which made multi hit was good for something before all single target skills was best except for on drg who had acc traits which helped them not miss as much.