I have never been a bomber gunner during WWII, nor have I ever played one on TV...but my father WAS.
Anyone dumb enough to come up from dead 6 was just that...dead. Anyone dumb enough to parallel a bomber 1000 yards out was (probably) going to have additional ventilation added to their aircraft.
Where AH and reality grossly diverge is where fighters attack bombers solo and where the bomber guns are all ganged together. As near as I can tell second hand, there were bad guys coming in from multiple angles (and not always at YOU, but very likely at someone near by) and every gunner chose whichever target looked the most dangerous. They NEVER (at least the training was very specific about this) fired on a fighter after closest approach; the odds didn't favor a hit and the guy coming in was more threatening.
...ok, so the Icons were harder to see and hit sprites were often lost in the excitement...
I've put my dad in a bomber gun and he did annoyingly well for an 80-something that doesn't fly AH. Way, way better than the punk kid with the good hand-eye coordination and no real-life experience, anyway.
The best view in the aircraft...Emerson nose turret on a B-24. Nothing but glass between you and the whole Pacific Ocean.