A few friends and I blasted through quiet a few strikes till we reached omnigul. We had the heroic modifier and we had about a total of 13 grasps drop from 110 kills. Did you just keep loading into strikes till you hit omnigul or did you play the strike playlist till omnigul popped up? You can no longer get the heroic modifier from omnigul saying you start on her that was a way they nerfed the drop rates.