The overabundance of magic arrows (And other items, but the thread isn't about that) kind of steps on the toes of the Ranger/Druid flaming arrows spell, and the entirety of the Arcane Archer subtype for fighter. If Larian wants to be including a bunch of different arrow types, then why not just homebrew a spell that only Rangers can use, and special Arcane Shots for the AA? Something like "Elemental Arrows" which would add X elemental effect to any piece of ammunition you fire?
Currently it kind of breaks my immersion, personally, to constantly be stumbling across magic arrows on the corpse of every basic, weak goblin archer, if they don't fire all three of their standard magic arrows before they get killed.