We don't know if we have completed the quest. Yes we got the ToM but that doesn't mean there isn't another portion unlocked after all 50 fragments are found. As for Bungie giving an answer on this, they've already stated that they will not tell you the steps to unlock any items/weapons/shaders/emblems. All we have to go on is what is stated in the game. Couple that with the fact that the subclass emblems stated they were unlocked from completing "Path of the [insert subclass]" quests which we did before TTK released and got the class item instead, there is a strong possibility that there is more to the "Old Hunger" quest. The emblems were eventually gotten from a separate quest that had a different name but were still considered a part of the "Path of the [insert subclass]" quests. So basically, getting an armor piece/weapon (even an exotic) does not necessarily mean the quest line is done. Also, no step in the "Old Hunger" quest line stated a shader as a reward iirc.

Well it never stated any rewards because once you kill the Wizard at the Phobos base it said 'Unknown rewards' so that's probably where a LOT of the skepticism came from.

Well anytime it states "Unknown rewards" that means either it's an exotic item or nightfall tier rewards and last time I checked, shaders/emblems don't fall in to that loot table.

They do. It did for the one from Shaxx. Wolfsgrin, but you are right. But you do have to get all 50 no doubt

IIRC the quest that gave Wolfsgrin actually had a shader listed as one of the rewards.