I'd say use it on a PvP necro warrior. Take advantage of the 100% fire damage by using corpse skin. Basic PvP Mods... hit spell, hld, and whatever else you need: SSI, dci, hci, etc. Bokutos are too low damage to really benefit from any leech mods. I would probably max out lightning, hld, and dci (to overcap your characters dci in order to combat hld).