Quiver is the worst shadowshot perk. Black hole is far better and I'm glad quiver is temporarily removed because it allowed me to realise how bad and useless it is. You can get a maximum of 3 kills if all arrows and direct hits, that's all it's useful for. The range is terrible and the timer is heavily reduced. Black hole however, can get you a kill straight off the bat, and then tether possibly the other 5 enemies in the team, for a long period of time. By using quiver you're basically preventing yourself from getting the most out of the bow by suppressing/weakening enemies. That's the best part about it. Also, if you miss a supered enemy with black hole you've got to be pretty horrid.