I find copying Page layout L->R and vice versa very strange if it is used just to have the same content independent from whether it is a L or R page and makes the master page system look more complicated than it is imo.
Can we have an option, for example a “page independent” checkbox that can be checked to reduce the master page to a single page that is used for both L and R pages?
As an afterthought: Can we have a visual indicator if a text frame is connected to another on the opposite page? I had it multiple times when I forgot that I had copied the layout, then edited the text content on one side and the other side was changed as well.