Actually all they nerfed was the time required between ultra kills. I used my last 12 Three of Coins today and got 3 exotics. Scourge of Winter mission, wait about 5-6 minutes between each killing of Draksis. It's still faster than strikes and better drop rate from my experience. I used to farm strikes and would go through at least 8 before getting an exotic. I don't have that issue anymore.