My friend mentioned to me a few days ago that the Passive that buffs Rocket skills is really good, but none of the skill runes that make rockets are very good. As a result, it might be a good idea to create some skills that cut out the middle man and just deal damage with rockets. Then the rocket DH might become an actual build, rather than just a curiosity. Possible ideas:

The Peacemaker: Fires a missile over an area which explodes, raining rockets down on the enemies below for X% weapon damage (think the rocket weapon that Tony Stark previewed at the beginning of Iron Man 1)

Vault-Broadside: Shoot out 10 rockets at the nearest enemies as you tumble, dealing X% weapon damage. (New rune, turns Vault into an attack)

Maybe some stuff like that could be useful. I haven't played much of the Demon Hunter, but I sensed from when I looked at the skills most people use on her that the DH doesn't have a lot of AoE spells. Something like the "Peacemaker" idea could give her an edge. Just a thought.