I feel that one of the biggest factors that goes unaddressed in AN classes is the fear-tension-pain scenario. Classes should aim at eliminating the fear rather than emphasising pain relief and 'complications'.
1. Often they just don't know this stuff - they get taught medical things at uni
2. Like I said earlier, hospitals aren't there to create a warm and fuzzy process for you but to control a process. So I see them running these classes the way they do for a reason, which is why I promote private, independent childbirth classes. Birth is a life event, not a medical one. Seems to be the wrong way around at the moment though, big time...