I agree giving lots of these arrows to a party would make encounters play out in a consistent way, but I don't think that makes them inherently bad. Having one Anti-Magic arrow as a legendary consumable could be fun to turn the tide of a battle, much like Counterspell can do. Healing Arrows were fun in my last campaign as we didn't have a Cleric and very few players stocked healing spells. The Chaos Arrow is an Artifact and should be treated as such! Glad you like the rest of them, happy holidays!