Pool we went to yesterday had two family change and one disabled/family change, plus then mens and womens - so has a variety of options. In the UK growing up our local pool had a communal area in both mens and womens and also individual cubicles in both areas - so if you wanted privacy you would go in the individual cubicles and generally was only parents with children who went in the communal area. People here are much more open in the changing rooms than in the UK I think - certainly at the pools near me (I remember going swimming with DD when she was maybe 7 months and a naked lady in the shower offering to hold her for me, I was fine so I declined but I think DD might have tried to latch on if I had let the naked lady hold her :-))

I have been to pools in Europe where is all communal getting changed, men and women in all together, and also ones where is just cubicles some large and some small without separate areas.

Public toilets I don't think are in the same category as swimming pools myself but I would judge each situation individually. DD (3) does go into the mens toilets with DH if necessary - often at the MCG, maybe not the most pleasant of places but not somewhere I view as dangerous in anyway.

I think places like pools are put in a hard situation, there isn't an infinite amount of room to put lots of family change cubicles, I don't believe there is any hard evidence to support the fear of letting children age seven and up go into change rooms alone (and really if it is worry about children misbehaving then as parents we should be able to sort that one), and if they did anything would have to suit both men who are taking their daughters to the pool as well as vice versa. So I think the suggestion of over 6 going in their own sex change rooms is a good one, and as long as they make sure the pools are family friendly places (TBH if you didn't have children there is no way I would go to pool on a Saturday/Sunday morning as is mayhem) I don't believe there is danger lurking in the change rooms.