Well actually your post is more about how unlucky you, the author, are with gear. I have all three classes and right now I favor the warlock, his armor rating is low because it was designed that way, each class has a specific attribute and their exotic armor is applied to that attribute. Hunters have agility, titans have armor, and Warlocks have recovery. And even so warlocks have upgrades and armor that make them tougher. Skull of Dire Ahamkara makes them tougher while using nova bomb, Apotheosis Veil let's them regenerate health while using their super, and two upgrades, specifically a melee and super upgrade, make it to where they can take more damage. The classes are balanced, but they're made to fit a persons play style, wether it was an unstoppable tank, a lightning fast rogue, or a magic healer.