To me the bow is a pretty great weapon but it becomes almost useless in the later stages where they can just reflect it back at you so i got some suggestions for the bow.
Arrow impact: the arrow still gets reflected but it does unleashes a small shock wave damaging the bot barely as in 1/3 the damage
Arrow speed: The arrow becomes faster so that they have a less chance of dodging and a better chance of get hit by the arrow
Homing arrow: the arrow barely turns to the closet target but still kinda useful
Arrow length: like the arrow width upgrade but for better chance of hitting those who try to jump to avoid it
Super Arrow: you can charge up and let the arrow take 2 bars of power but it comes with 35% more width and length and 40% faster