I feel like I'm missing something with this skill. Dart-Splinters can do 180 dmg for 10 mana while Spirit Barrage does 190 dmg for 108 mana. Okay, so it can target in the back, that's nice I suppose (though surely not worth 10 times the cost) but so can Haunt which, runed, can do 288 dmg for 98 mana and can jump to multiple enemies. It just seems so much less efficient than either of these as a single-target skill. Even with the +mana rune it doesn't seem worth it over Dart or Haunt. (Haven't gotten to the other runes yet but they all sound lame.) Am I missing something?