imo, it should take on cleave's functionality. have two 180 cones with a radius of weapon range. every 4 frames it alternates the cone, hits every monster in that cone. also alternates the weapon, so 2h is just more dmg outright than dual wield. then 2h can be justified to be 5 frames.
TBH, I think this games running on the same engine it did 20 years ago. Cleave is a pretty easy thing to simulate by throwing out small aoe in a 5-15 degree radius. THE FACT WW still just deals damage in sequence makes me think they didn't know how to fix it. If they had do add splash damage to each hit. I think it'd work in the engine.