As per an earlier post in another DoT build thread on this forum, I'll suggest a variation of the OP's build:
Replace soul harvest or paranoia with Spirit Barrage - Well of Souls. The dps boost of channeling an essentially free 475+(65*3)% damage spell on elite packs is more effective than the damage boost of either soul harvest or paranoia. Combine with high Area Damage to make it even more effective. Also instead of recasting DoTs (especially Haunt) on elites to make sure you got a crit cast, just focus down the highest HP ones with SB.
Consider Piranhado instead of other Piranhas runes because it both stuns and gathers mobs. Since you're already using Grave Injustice, this will reset the cooldown very quickly. The gathering ability also allows you to spread Locust Swarm very fast, and lets your Area Damage be more effective.
For hardcore, Consuming Spirit for haunt is very effective, letting you build up a lot of health regen for elite packs (6k+/sec)
Replace soul harvest or paranoia with Spirit Barrage - Well of Souls. The dps boost of channeling an essentially free 475+(65*3)% damage spell on elite packs is more effective than the damage boost of either soul harvest or paranoia. Combine with high Area Damage to make it even more effective. Also instead of recasting DoTs (especially Haunt) on elites to make sure you got a crit cast, just focus down the highest HP ones with SB.
Consider Piranhado instead of other Piranhas runes because it both stuns and gathers mobs. Since you're already using Grave Injustice, this will reset the cooldown very quickly. The gathering ability also allows you to spread Locust Swarm very fast, and lets your Area Damage be more effective.
For hardcore, Consuming Spirit for haunt is very effective, letting you build up a lot of health regen for elite packs (6k+/sec)