Bungie has been working on the new subclasses for a while, balancing out and changing everything before the final builds of each new subclass skilltree. If they thought it was OP it would of been changed before release. They playtested and had people playtest the subclasses before TTK launched. If there was a problem with the class not working as intended if would of been dealth with. The Titan is the high armor class. They designed it that way. So if gets nerfed the other two should have their damage reduction lowered as well. They should not be as good as the Titans period.