My opinion has always been the difficulty and ramifications of the required modeling for the remote firing turrets. Unlike the gunner positions on any other plane, the gunners (except the tail gunner) do not have a gun actually at their position.
Why this matters . . . If I am in the top turret of a B-24, the two guns at my position are firing at the object. All other guns fire in that direction and converge at 600 yards IIRC. In the event the bogie I am shooting at is very close (say 100 feet away), the two guns I am aiming at him from my actual position will hit him. All the other guns are going to shoot around him and past him. Same if he is far away (say, 1000 yards). The shots converge at 600, then disperse all around the enemy . . . but the two guns at my position will still be aimed correctly and can ping him. (The dispersion is a mixed blessing -- it can act as a shotgun making at least a few pings more likely, but I would hazard a guess that very few gunners if any actively try to hit planes with guns other than the two they are truly aiming.)
Take the B-29's remote turrets. The gunners in the waist look through a bubble, and see that bogie 100 feet away. With the current coding, the gunner puts his gunsight on the bogie and fires . . . and because he has no guns actually at his position, none of the bullets actually hit the target. In other words, unless that plane is at convergence the gunner has to aim someplace other than the enemy plane to have any hope of hitting him.
Real life B-29 gunners had a simple computer that would change the convergence of the remote turrets based on the distance the gunner input. In other words, he could set the turrets to converge on that target 100 yards, 500 yards, 1000 yards away, and the turrets would respond accordingly. No such thing (yet) in AH. And since we have the magically floating distance number above any enemy icon, gunners in AH with such a capability would decimate any attacking fighter quite easily.
Therefore, it is my opinion that the coding required to make the B-29's guns anything less than useless would actually be so imbalancing in favor of bombers (all bombers, because why would you NOT give other formations the same capability once an adjustable convergence is coded?), that the liklihood of it ever being introduced is small.