Quote Originally Posted by Aidoru View Post
As great as stat down debuffs are, most people are factoring in that it has a 100% affliction rate, which they do not. I'm not sure if we'll see any future event bosses that have high affliction resistance such as the wind disaster raid boss but if that ever becomes the case, it would be questionable to choose that over a buff (if you didn't have the option to choose both) and even so, they still miss on a regular basis even on these current/past bosses. So while the gain from using it is much greater when calculated, don't forget the loss from it from missing is just as much of a factor.
That's the reason, why mordred is one of the best legendary in boss fight. He increases the chance of applying debuffs and provides more control.