I got a letter from a reader who wanted to know my opinion on Cloak of Shadows, as he thinks it gives rogues too much of an advantage over his warlock in PvP. He wonders whether Blizzard gave Cloak of Shadows to rogues so that they could escape mages crowd control, with other cloth casters ending up as the victims of this class review. Well, I can't say, it is hard to know what went through the head of the developers when they made a particular change. But I agree that I too hate getting stunlocked by a rogue, and if my only chance was to fear the attacker, I would be annoyed if he had an ability that made him basically immune against all I could do.
But while we could discuss class balance in PvP endlessly, in the end it all sounds like the rock complaining that he always loses against paper in a game of rock-paper-scissors. I don't think it is humanly possible to design 9 classes with 3 talent trees each in a way that each class/talent combo has exactly a 50:50 win chance against each other class/talent combo. My holy priest hates being attacked by a rogue in PvP, my protection warrior loves them, because they are one of the few classes that attacks from close enough to hit them, and I'm well protected enough by armor so I don't die during the initial stunlock. Stealth, stuns, and Cloak of Shadows magic immunity sure are annoying, but take them away and you end up with a rogue that couldn't win a PvP combat against any other class. It is not as if warlocks are otherwise underpowered in PvP, so having some classes that regularly beat them is necessary. Unless you only fight against people who have the same class and talent spec, every single PvP fight in World of Warcraft is unfair and unbalanced. Only the sum of all these imbalances comes out even enough to not make one class all powerful.