Hawkian,
Prior to patch, there was a consistent occurance in the reward system. Every time I lveled rahool, I got a legendary. There was never an instance where I did not. Post patch, not once. Looking at my experience from start to finish, this is not indicative of chance.
Additionally, I clean through all weekly and daily activities. The only time I have ever run across a shard was by dismantling and, up until 3 days ago, doing the raid on normal. That's it. Others have shared this exact same experience. So the question therein is why are some experiences consistent across one set of players but not the others? Chance has nothing to do with it. Chance would have netted me a single shard from pve, publics, etc. In 90 hours, I can't have been rolling the same number on the dice.
Yet, I have about 10 legendary items (one boot, gauntlet, chest and rest weapons), 4 exotics, and a whooooooooooole lot of energies. Others have not had the dice rolled in their favor with as many hours as I have put in. It makes no sense, statistically.
Here is the biggest problem: it puts good players at a disadvantage. I was carrying a level 28 and 29 team in a Nightfall last week when I had been stuck at lvl 27 for two weeks. I spent my marks for my gear which I rarely get just so I could scratch by and get to lvl 27 and, subsequently, have a chance to survive nightfall and a raid.
Bungie needs to open up about how this system works and how these variables are calculated.