Usually, none. Rogue has so many damage related passives and aoe damage that having one with long cooldown feels unnecessary. Shadow imbuement into twisting blades, or barrage, or rapid fire, or traps all do so much AoE at such little cooldown that rain of arrows feels almost always pointless. Especially so with word of Hakan when you could have CDR or damage or passive ranks on your amulet. The only unique you really are looking for is the penitent greaves.