Currently when a projectile is released it follows the unit around, but the devs are not checking the range of the object that is firing the projectile. If an object exits the range of a projectile unit, just cancel the projectile. This way people who want to micro can do at the same time careless people will be peppered with arrows.
This is how all the RTS games with homing projectiles do and also please add miss chance to siege units for living and non living targets.
we can also avoid strange and goofy looking projectiles that fire into the emptiness and which takes weird arcs.