It's great for Battlegrounds, where you're usually standing back slapping DoTs on everything. In Arena, it packs a lot of punch, but you go down fast to Warriors and Rogues or when focus fired. Of course, if all of those foes have 4/5 DoTs on them, you can make a significant contribution even from the ground xD
On that note, I just thought of a badass level 80 skill:
Shallow Grave
When you die in a party or raid group, refreshes all of your debuffs on enemies, but they do 50% damage. These debuffs cannot be dispelled with the exception of Unstable Affliction.
Ultimate backup plan: not too overpowered since the Resilience nerf and healers, but if your partner is tough you can win anyway.