DWS is for Aimed shot, which doubles your crit multiplier, giving you double damage Adrenaline attacks. So it makes a thrower synergize with FoTW and adds roughly 35% physical damage. It also adds a lot of smoothness to leveling, since at level 9 with aimed shot + sb + double crit shadowstar bug combined with sb bug you will have 3-20x4 attacks which can instakill mobs off raw damage. Also drow doesn't give dex to damage with thrown.
People think shuriken and think procs. Raw damage to the face works well too though. This is a shiradi Aimed Shot with shadowstar. A fury adrenaline one would hit 5x as hard. Even bugged without the SB crit multiplier, it still is a decent attack.
Ranger also gives unbridled wrath many snipershot combo.