Hey soul killer, I never said Delirium was the absolute choice was nor did I recommend it for the best overall performance, if you were paying attention.PvP Bone Necro doesnt need defence, hes not a BvB.
Necs need skillz, resists, life and FCR.
Shako has most of that stuff and is very attractive any caster, and the str req. on those high def helms are steep.
But hey dude, do w/e you feel comfortable with, although i dont recommend it.
On the getting hit part, that is poor logic. You are saying that CTC Mind Blast is bad because you are going to get hit. I am saying that you might get hit, so it wouldn't be bad to have CTC Mind Blast to blast them back when they hit you. But I agree on the defense part, because of the scaling of Defense/Attack Rating in the Chance to Hit Formula (It's quite complex to understand at first but basically the first part of the formula, the one that factors only Defense and AR, says that one point in Defense would counteract much more than one point in AR).Shako is alright until you come across a nice Circlet that blows it out of the water.
The CTC Mind Blast on Delirium only works when you get hit. Something which you don't want happening in PvP, or at all for that matter.
Oh, and every little bit of defense helps. 15% ed is the way to go with everything, ideally... in a perfect world...