Different arrows used to do different damage types some where piercing some where Blunt etc etc. that was removed from the game some time ago, so I see no reason to keep the 8 different plain arrows.

I would like to see different damage type arrows reimplemented, Onion Arrows Could be your base arrows, Piercing Arrows Could be your Line AoE arrows, then you have your Elemental Arrows. the chances of this happening are slim to none, given the recent track record of highly Disappointing "Seen it before in 5000 other MMO's" streak there on.