What happens when the RPG shooter is in close proximity with the light infantry troopers that you just dropped off? You gonna waste a squad of friendlies to save the chopper?
It's roughly the same problem that tanks have when using "active armor" systems that explode when hit with an AT missile. Dismounted infantry probably doesn't want to be anywhere near the tank being attacked.
If a shotgun type of shell was used the lethal range would be
Short. I would also think that most rockets would be fired from the position of the enemy which should be different than your troops so their is a natural tendency to miss your troops, in fact if a rocket is to hit a object, the return path is almost the same so the gun system will some times get a free bad guy.
Any computer system could paint a black out area that it would not cover too.
The computer has to know where you are but this is not a problem anymore.
If you have rocket protection you could also fly higher. This makes it a lot easier to paint safe areas in the protection zone.
If a F15 could shoot down most incoming missiles would not this change the way war is fought? For a kill the enemy might have to launch 20 missiles instead of 2.
It is a good idea and could be done.