I would love to be able to fill up the gunner positions. But in order to do that, I would suggest that if you only have 1 gunner, everything the way it is now stays the same. If you have 2 or more gunners, only that gun that is occupied will fire on all 3 bombers. IE: if the top turret and tail is occupied, then only the upper turret will fire on all the formation bombers when he pulls the trigger. The tail gunner will fire when he pulls the trigger. I believe having this setup would bring a happy medium.
As it is now, it is very hard to defend yourself in a bomber when u have 2 or more bogey's attacking you. You can only shot at 1 if your by yourself. If you happen to have a gunner with you, then u can track 2. 3 or more bogey's and it all done.