The overall problem with bomloads, is that with increasing number of bombs, also increases number of hits. So by using historical bombloads, we will get strange result, when it is filtered by game engine. Here is my theory, how it should be implemented, to work in current engine:
Fighters should become main aircraft for attacking airfields.
ZERO carries 2x60kg bombs. Since number of hits is most important for closing airfields, this type of plane should carry most bombs. Change should be something like 8x15kg bombs (same bombload)
Light attack bombers (mostly 1E) - they should be main ground support.
ANN/MARY carries 1x250 kg bomb. Since number of hits is most important for eliminating LCU devices, not size of bomb, they should carry more devices, than 2E bombers (so more, than 4). Change should be something like 5x50kg
2E bombers - heaviest tactical support. 4 devices seems to work OK, anything more is streching game engine, but because we need unity in same class models, bombs can be represented as "sticks" (TM by NEMO) of 2 bombs each. Japanese bombers do not carry more than 4 250 kg bombs (at least in current Scenarios), but quite a lots of Allied 2E bombers carry more.
As a side note - it seems, that size of bomb is more important during checking if plane hit on ground will be destroyed. Lots of smaller bombs generate more hits, but planes tend to be only damaged.
4E bombers - ONLY STRATEGIC ATTACKS. They should barely hit anything in support role. The whole bombload should be represent as ONE (maximum TWO) device. Something like one large bomb, with effect of sum of all carried bombs. That way they are only good for attacking industry, or destroying stockpiles at bases, as they generally score less hits, than smaller planes (although their hits are sure kill). That can create problem with naval attacks, but bombload, in this case, can represent 1-2 bombs effect, but have greater accuracy (to simulate releasing of whole bomb-bay in one go).
To sum up:
4E - 1, or 2 devices
2E - 2-4 devices (NO MORE!)
1E - more, than 4 devices for ground attacks (they can still carry ONE large bomb against ships)
Fighters - more, than 4 devices for ground attacks