Could not agree more, Desto warlocks almost never use corruption, why use your 2.5 secs for it when you can pew pew with a bolt, however, some fights is ok to lose that little bit of dps to cast corruption, on archi for example, where u send alot of time not spammin bolts since your being stalked by fire. Like everything else, its 100% dependant on the fight, if your healers are struggling to keep up, then good time to use it 2 =P