You'll lose to a Doctrine at pretty much any range with pretty much any AR but SUROS with Focus Fire at pulse rifle distance. You simply can't use an overpowered weapon as a baseline for measurement. By that logic, the entire Hand Cannon class of weapons are nearly useless. Doctrine may be a large-clipped, overaccurate game of bullet hell of a High RoF AR, but it has damage falloff. Hard Light does not. Ambushing works against Doctrine, as does kiting them to engage you t distances their bullets aren't effective as anything but stagger. Strafe always when firing fully automatically; it makes the recoil and screen shaking easier to manage. There's tricks to learn before it gets good in your hands, but it's good.