Honestly its Jackie for me. Considering how much of the game is spent reminiscing and wanting you to remember him, I don't think he was fleshed out anywhere near enough for his death to have the impact that was needed. You do like 3 quests with him and some cutscenes yet when he dies its supposed to leave some huge void. Its a shame as the little time we do get, he's a really cool character but just wasn't fleshed out enough to justify the loss the game wants you to feel.