Wal-Mart has had "family bathrooms" for forever. Mainly a bathroom where a family is encouraged to go in, if they need to, like for a baby or something. One of my ex's and I would use it all the time since she had a toddler and we'd both need to go. Just so much simpler.
That being said, I'm not exactly sure how I feel about "unisex" bathrooms themselves. Being a guy, I know what happens inside of a guys restroom. Dunno many women that would want to punish themselves like that. But, I do feel like it would be weird. I still have the mindset that bathrooms are private moments. People are in there talking. On their cell phones. Having conversations with the person in the stall next to them. And me, well, I'm just quiet.
Also, most mens restrooms around here might have 3-4 urinals, with only one...maybe 2...actual stalls with a toilet. Since most women need the ability to sit to use the restroom, I feel that that could be more of a embarrassing moment then anything as well. Already having to stand there and basically stare down while you wait for a stall can feel pretty weird to me.
Now, as far as Starship Troopers goes, this isn't really a bathroom (restroom) but mainly just showers and a changing room. I don't see any problem with that. However, history has shown (many times by the YMCA) that a changing room isn't the most wholesome place in the world. Ultimately, I feel it would be best for everyone if there was always opposite sex changing rooms and bathrooms.