This still leads back to the balance between guaranteed rewards and luck-based rewards. If the guaranteed reward outweighs the (low) potential for a random reward, people will not spend twice as long grinding through trash-mobs "just in case". Right now, I need to complete 25 Strikes. I'm frankly not worried about what "might" drop, because I still have to kill a fair number of trash-mobs to finish anyway, and I'm much more concerned with receiving my exotic at the end. If you wanna kill trash, find players who want to do the same. I don't, and my motives for it aren't less efficient because of it, just different than yours.