black arrow is horrible.
that is totally unbalanced and would ruine tourneys.
poisonous arrow i like, mainly because I like the idea of using special mushrooms to make arrows, it gives poisonous foods a point hehe.
guided one I dont totally like because I dont like the idea of garunteed hits, bypassing the AC and WC stuff.
maybe the option of shooting a volley of arrows at once could be neat...more likely to hit something or maybe more than one thing but would cost 3 arrows or 5 or whatever each shot.
For better accuracy, I think instead of thinking up crazy arrows for bows, there should instead be crossbows that fire bolts. Bolts would be made of metal so they would be slightly more expensive to make but would be alot more accurate because they would travel in straight lines up to so many units then lose altitude.