Golden gun gives no protection from anything, makes you a burning target for everyone, and there are 3 shots, 4 if you have the exotic helmet, that you can miss or get killed before you can use, or the timer expires so that balances out the risk/reward. Arc blade requires you to get really close to your enemy. Any player worth their salt will not allow this, and if it does happen, the Hunter either planned an ambush or the players were all huddled together like idiots not watching the radar, their surroundings or listening for the telltale crackle of arc energy. The damage reduction is only for arc damage as well. The Titan also has a melee that gives him overshield, which cancels out with the Warlock, so moot point.