At this point, I feel like this game is self-aware and actively trying to annoy me in any way possible. So after doing the Raid for the third time and only receiving a so-so shotgun and a second Chatterwhite while still not having obtained any piece of Raid armor, I go and do the Nightfall. Guess what? For the first time I actually got an Exotic from it!
Sunbreakers.
The one piece of Exotic armor I already own.
That thing that has been sold by Xur for three out of four visits.
C'mon, just give me something...
I'll get my FWC Rank to 2 for the HC/SR Chest Armor and maybe collect some Vanguard Marks for a Rare Sparrow, but then I'm ready to put this game down for a while and go to Mordor. I just have nothing to work towards in Destiny anymore... I have no real use for the vendor Legendaries, I can't control getting Exotic bounties or what Exotic bounties I'll get, I can't influence the dice rolls on whether I'll get Raid armor or not, I can't influence my chances of getting loot from the Crucible, I cannot choose to take on tougher enemies to get a better chance at loot, etc.
The only reliable sources for late-end-game progression are Xur ( only on weekends ), The Raid ( weekly lockout ) and Nightfall ( weekly lockout ), all three of which ( by pure chance and RNG ) have pretty consistently not given me anything I need to make any sort of progress.