Multiple gunners was interesting in WB, but it definitely had its drawbacks apart from the ackstarring. Often you'd get guys joining who would obviously just pass out or something, and then when the bad guys put in an appearance, they were taking up a spot snoring and no one else could get on.
I love the AH bomber gunnery, the zone fire system simulates most bomber defense situations in WWII, and as Puck has already pointed out, having an auto gunner inevitably leads to whining about it being too accurate/too hopeless--and god knows these boards don't need any more whining. (Of course, the problem with WB is that the bomber guns were completely porked anyway, jumping and twitching like an electrocuted rodent).
Revvin makes a good point about the vulnerability of a lone bomber against two fighters who know what they are doing in AH, but the way I look at it, if you don't fly in a realistic fashion, there's a limit to how realistic you should expect the features should be. Sure you are vulnerable--but that's what a wingman or two is for. . .