You should be able to hit a mob with all three rays from about 5 blocks away. I tried this while we were testing Shaman's range, due to the "only one basic attack can exist for Shaman at a time" thing making certain attack speeds have a shorter effective range. Super Fast's range is short enough to consistently hit mobs, so you absolutely can make that range good. The build you provided has oodles of walk speed so you can easily dance around mobs while hitting them with all three rays for the full DPS(note it hits 30k or so while you're in your totem), and honestly? "This thing is overwhelmingly and brokenly strong, so this other thing, despite also being ridiculously strong, looks bad and needs a buff." Not a good reason.