I don't know if I missed something in the thread, but where do you get the idea that Illidan is perma-dead? His soul is alive and very kicking during the DH campaign (I mean the actual campaign, not the starting zone) He just can't get to his body and is being hunted through the TN, where all demon souls go. Plus he specifically says he cannot die normally in the starting zone, which is before his presumed death at the BT, so he only said so and didn't prove it at the time. But as far as I understood the reason his body was locked in stasis along with the other DHs was because then their souls can not come back to those bodies and if the bodies still exist they can also not reform new ones. Though I'm not sure if the last part is something I kind of made up for the whole "preserving their bodes-thing" to make sense for me