With Destiny as much as the Engram issue was a major annoyance to me especially with needing legendary weapons to upgrade the ones you are using. I can't bring myself to play the game anymore since most of the game plays the exactly the same way, you have the PvP which now if you have people with Vault of Glass gear will just destroy the map or all the PvE encounters start to feel like the exact same mission.
What will bring me back to the game is if they decide to somehow figure a way to improve the games experience for the content that shipped with the game, for otherwise I just can't see myself spending the time trying to improve my gear to increase my level to play the new content since both Vault of Glass and Queen's Wrath are both locked behind gear levels.
Now, its not the grind that bugs me for I have played MMO's for years done a lot of grinding for cash, loot drops, or even reputation. The problem is when I get tired of the grind there is something else to do or different methods to grind for what I want to break the repetition, Destiny doesn't really offer that.
Edit:
Something I should add, I don't have my own personal copy of Destiny yet for I am playing a friends copy for I couldn't afford or justify the cost of buying a console and the game and my 360 died. Now my friend who is letting my play his copy finished the story part of the game and has been extremely frustrated by the RNG elements of the game trying to level. He figures he has spend over 20 hours at level 20 and only since this patch been able to get to 21.