I spend my whole spring bowfishing the San Joaquin delta- yes I'm addicted!
#1 most important factor is arrow flight- just like in bowhunting,
Close behind is arrow weight. i like those yellow jackets but any fiberglass arrow works. I notice a difference in penetration between the heavy Alu fish arrows and the heavier yellowjackets.
If you are shooting fish on the surface or only a foot or so deep- light bows are fine. The same bow shooting fish 3' or more deep is sorely lacking. When we are shooting fish 4' deep or more I use a compound thats 55#-60# or more. [don't shoot me for the C word, my shoulder can't handle 300 shots with a heavy recurve at a steep angle downward like that.
As I said, don't discount arrow flight. When you shoot into the water there should be no splash what-so -ever. It should just be a sucking sound of arrow hitting water. You may have to play with the heavier points to get good arrow flight with a light # recurve to get good consistent arrow flight. It helps to have a riser with arrow rest that you can adjust, IMO.