I guess I would prefer complete privacy in the restroom, but if I let the gaps bother me, I could never leave the house, so I don't let it. I do find it rather funny that it seems to really bother some foreign visitors. When I was in college, travelling around Europe and staying in Youth Hostels, we were all mortified to discover we had to shower in open showers! Partial walls, but no door or curtains. Also, one time in Mexico, we had 18 girls sharing 2 showers. They were 2 deep, meaning you had to walk through one in order to get to the second one. In order for all of us to get ready each morning, we just lined up and when one person came out, another came in. You were guaranteed to walk past one naked person or have a person walk past you naked. Ahhh, the memories!
I think this bothered me much more when I was young. I worry more about sounds and smells that anything else. And full doors don't mask that. That's way more embarrassing than someone just being able to see you perched on the toilet as they walk by. I've never really encountered any weirdos, but the random toddler peeking in to say Hi, is rather comical since I now know what it's like to keep one corralled in the bathroom until they learn proper bathroom etiquette.
By the way, removing stall doors is still alive and well today. My daughter's grade school removed the doors in the boys bathroom last year after someone pooped in the sink! This was kind of a last straw after they already made the boys go in pairs, so they could tattle on each other, and locked all of the bathrooms except the one right by the office. When neither of those tactics worked, they finally removed the stall doors. I haven't heard any bathroom stories recently, so maybe it's working.