There are only a few legitimate reasons to die. Skill, lag, and opposing teams' teamwork. No reason to blame weapon types or certain weapons. If you're dying to shotguns, use your mini map more and stop rushing everywhere. If you die to fusions a lot, listen carefully and don't blindly rush around corners. If you're dying to auto rifles, use cover more and move faster. The net code is bad in this game so I trade quite a bit (especially since I'm an in your face shoulder charging type of Titan) when I melee. More often than not I'll stumble into a room with several people in it and I'll go down. If you're patient or aware of your surroundings, you die a lot less. I know this from direct experience as before I started trying in the crucible, my kdr was at about .81 and has slowly gotten better the more I play.