1. In observing fights between pairs of bases, I have noticed that much more often than the fight ending because one side gradually grinds down and pushes back the other to establish true air (or ground) superiority, it ends when someone on one side or the other ups a formation of Lancasters, B24s, or B17s and bombs the crap out of the hangars. This is unless they start out by bombing the hangars, in which case the fight never develops in the first place.
2. These heavies were meant for devastating industry/cities from high altitudes. The bomb load of a formation, combined with the easy accuracy of the level-bombing sites at lower altitudes, makes them almost ridiculous overkill for hangar dropping. They also render fighter-bombers, which are historically more along the lines of what you would expect to be used on such targets, almost superfluous by comparison.
3. The crux of the problem with buffs is that with a decent gunner they are nigh un-interceptable. Whereas in reality, daylight bombing with unescorted bombers proved to be disastrously costly, even with large formations, in the AHII MA it is much easier to land 3 kills of fighters than it is to hunt buffs, and everyone knows it. Thus they most often go unintercepted. To start with, a formation can under ideal conditions point up to 18 .50 caliber machine guns at a single fighter. (Fighter pilots, unlike buff pilots, do not have the option of automatically upping with 2 wingmen to help them shoot down buffs). This is a situation that makes strafing WWs look like a good bet by comparison. Because there are no convergence issues, and because a flight of buffs on autopilot is an artificially rock-solid gun platform, the effective range of all these guns is typically at least half-again that of the fighter attacking them. There is no attacking angle that allows a fighter to really take a shot at the buffs without giving them an equally good shot at him. Front-quarter or head-on attacks work for expert shots in birds bristling with cannon, but not too often for average attackers in more lightly armed planes. Furthermore, the most heavily armed planes, like 110s, 190 A8s, Mossies, etc, are not nearly as common as planes more suited to a fighter-on-fighter role, and tend to climb slowly, a definite handicap when asked to intercept buffs on short notice.
Basically, the result of all this is that unescorted buffs, which should be a prized target, are in fact avoided and usually succeed in their mission. The role of escort is almost superfluous, it could almost be said that escorts in the AH MA basically just steal kills from the buff gunners.
4. My solution to the problem? Consider disabling/perking formations for the heaviest buffs. This would tend to reduce both destructive capability and defensive firepower. Alternatively, at least make it impossible to link all defensive guns together, so that attacking fighters would be facing say 6 .50 caliber tailguns firing at them instead of 18 guns.