Striker doesn't have an overshield. They can't turn invisible. They have high movement speed but the lowest base melee range. They have no weapon handling perks. They do not have an innate defensive move such as blink or shadestep. Their orb generation is limited. They're the CQC class - as such, they have high armor, a OHK melee and powerful melee abilities, and a couple of good grenades. And health regen that only procs on kill. And a shutdown super. They fit their role perfectly. The subclass is fine.