Maybe I'd like to use glowstone, or a sword, instead of an arrow.
So perhaps a config option to set this? (With the option of, by default, minecraft:arrow)

What's the problem with the arrow? It's not meant to be used in survival, so it's not really an issue

Well the issue is that this can be used in survival.
Lets say I might have an unobtainable item, such as a creative battery from a tech mod.
Maybe I would be able to set it to that?

But why would you?