Yeah poison and firearrows would be a nice addition for that arrow variety.
But in this setting i kinda would assume that firearrows wouldnt behave like they normally do in highfantasy.
Meaning they maybe should do much less damage and be less acurate but do morale damage and ofc (because that has to be in ever fantasy game) do
more damage against trolls…
Poison could even be extendet to meele weapons and/but that kinda leads into thinking about everything related thieve-class mechanics. Wich is maybe something for an expansion because it could entail a lot of new gameplay features (Sneak, Steal, Ambush etc.) and maybe a different start option (Battlebrothers or Thievebrothers)
Also another thing but that depends on another feature i will suggest in another thread: Lances for Horseback combat