I think for a good action economy everything must be in line.
Fire Arrows must be tar arrows and ignite them must cost a action.
Fire arrows make fire plus normal damage so you make maybe less then 2 normal arrows but fire prevent maybe troll regeneration or ignite other effects which is the big bonus.
To make fire arrows alsways the best choice is bad.
The same with maybe a Magic weapon.
Magic Weapon which glows but have no combat bonus, Hey dont need a Torch!
Holy Weapon ?
Sorry but Poison a holy blade wtf go away., =D
Such RPG Elements where nice.