Bungie has never had a single clue on how to blend the grind into natural gameplay. They don't know how to make repeatable content fun, only how to make it take as long as possible to complete each round. Look at their bounties for playlist activities. Almost every-single-one requires you to essentially not play the activity as intended and actively fight against your own teammates so you can complete them. Didn't get that final precision blow with your handcannon? Tough sh*t. Do it again. The easiest fix to something like that is have any assist count toward bounties requiring kills, which is almost all of them, but make the final blow with a specific weapon or ability count the most. Done. Now players can get their bounties done while actually playing the activity like they're meant to. Same for their damn exotic catalyst chores....I mean quests... Have assists count but final blows with the weapon count more. Done. Players still gotta put in the work but the game would hide most of that grind behind simply playing the activity normally.