I fly bombers a fair amount, especially in scenarios. I almost never use the external view. It's not much hindrance to jump around and look around from the gun positions. True, external gives you a bit better view, but I like the more-realistic views from the gun positions better. I also tend to fly my plane from the pilot position, not gunner position, when adjusting courses in formation with others, again because it is more realistic to me, and so I like it better. I don't think I'd argue for precluding others from using less-realistic ways, though, as long as it's not a replacement for the way I prefer.
For attacking bombers, there are people who are much, much better at it than I am. For me, attacking B-17's, B-24's, B-26's, or even Lancs is never a low-risk proposition.
For being attacked in bombers, there are certainly some folks who could shoot down all my bombers without me getting them, but most of the time, I'll kill or disable at least one attacker before I'm down unless I'm in something like B-25C's.