I feel like there is validity to this theory. I don't remember where I heard this, (it might have been from one of the ride alongs)that drops take into account weapon types in your inventory. The last few weeks I put a lot of stuff in the vault and on to my seacond character and received what I would consider better drops. In the last few weeks I received. Patience and time two suros and the fourth horseman from nightfalls and even daily heroics. This week with fairly full inventories I got ten coins from the nightfall twice. Ugh! I feel like spending more time considering what you want to take into a mission and leaving the rest may help your chances. It is still obviously random but if it helps it helps. I think carrying only two to three items in each categories inventories would be a good set up. One exotic in each with one or two legendaries might be a good start.