I think the most effective way to balance the weapons would be to make range an even bigger factor. For example; Lrof Pulses and scouts have great target acquisition and no damage drop of at range but Hrof pulses and scouts and more inaccurate and deal significantly less damage outside of their intended range. This also would be the same for shotguns. Make High impact ones deal loads of damage up close but have almost no range and as the impact gets lower the range gets higher. This would make them strong in PvE since you can still destroy yellow bars up close but would bring them into line a bit more in the cruicible.