I want to thank everyone....
I'm sorry if I came off wrong Rapier as I have the up most respect for you in this community.
To answer your question with my opinion.
Does the modeling in the game force these planes (and the fighters of course) to be flown realisitically? No it doesn't, and IMO never should. Many planes in AH could be pushed harder and do things IRL that no sane crew would ever do unless their life was on the line. Bombers could do some pretty incredible things but like you said most of these maneuvers would throw the crew around or cause other problems.
HTC has modeled these aircraft according to their information and they've given us a sandbox to play in and do whatever we want with these planes within the rules of the game. Some of this stuff can be seen as dweeby to some while for others it's their source of fun. When the B29's came out one of the first things I did was take off and find a tank battle to dive bomb with it. Why? Because I'm not sane, and everyone that was around got a great laugh out of it.
One reason I love AH is the fact that I get to take planes and push them in ways they were never used, BUT, had the ability to do. My favorite past time is flying the B25C into furballs and dogfighting, something it was NEVER ment to do. I die 99.8% of the time when I do this, but there is that 0.02% chance that I will get multiple A2A kills with the thing and get a change to land them....that is what I play the game for.

If HTC were to restrict bombers to only flying certain ways and only being able to drop bombs in certain ways it would most likely kill the game for me.
Secondly....
Is the gunnery model realistic?Yes and no. The guns fire like they should and with trajectories like they should, however, bomber gunners never were "in-tune" with one another like they are here. What you have to remember is the pilot of a bomber is doing the jobs of multiple men, I mean when flying a B17 formation 1 player is doing the jobs of 30 men! If the player could only fire 1 gun at a time it would mean the death of a bomber as the fighter pilot would only be facing a fraction of the firepower the plane had IRL. Secondly even though bomber defensive fire wasn't as concentrated IRL like it is in here, it was still a pretty big threat.
Although not completely realistic I feel that bomber gunnery in Aces High is a good balance. Yes a player controlling 36 x .50s on a set of B17s is a bit much, however, you should be attacking those bombers with a wingman anyway. Seriously, two fighters attacking a set of bombers GREATLY increases the chances of killing them by splitting their defensive fire, even with a gunner on board.