I would like to know the same thing. I have a 50 Dark/dark/levithian and while I do have some IO sets in his build, I get the feeling like Im shooting in the dark (pun intended) and Im not making wise choices.
The best things I can think of would probably be to aim for ranged defense, recharge then try to get some global accuracy.
Of course between your attacks, darkest night, fearsom stare, and fluffy, anything you're fighting is probably already at the to-hit floor against you.
Probably prioritize recharge. Get tar patch and fearsome stare back faster while boosting your damage output.
Im trying to figure out how one would IO out a dark/Dark, she's still low level so i have some time to get the things i need but the question i have is: Is IO'ing a Corruptor alot like IO'ing a blaster? Do i try and cap ranged def?