>DEX is required to make the bows deal more damage
>Bows can infinitely become stronger through str/dex upgrades
Actually, I think being more accurate with a bow would probably be more closely tied to an Intelligence or Perception stat. Being able to quickly estimate how much you need to compensate for windage and the speed at which your target is moving.
>game lets you retrieve arrows/bolts like in real life
It doesn't matter how well you can calculate if you can't implement those calculations. Dexterity scaling with bows measures how fine-tuned the user is with making the small adjustments that heavily influence the arrow's final behaviour.
>speed effects how quickly you swing your weapon
>DEX makes physical skills stronger
I think bows should require the luck stat, because if you shoot in the general direction of the enemy you're more likely to hit them if you're lucky.