You're talking about the small accordion door that sections the bathroom from the bed area, not the door (wood) between the living front area, and the back bedroom/bath area. We have used the accordion divider for one week when my mother traveled with us 7 years ago. Most people probably never use it. It is very, very rarely used and there would be no way to put in anything but an accordion divider there to divide that section. Now, you might not agree with the layout, but for most people this isn't a problem.
Luckily there are all kinds of coaches out there, so there is one for everyone. And no coach is perfect. Our friends had a CC, had several problems with it.
Barb