Lovely bathroom and a great barn door detail........

I would select an obscure glass that has a traditional pattern. You can find a pattern that is reminiscent of the traditional look that you have created for your bathroom. If you are unable to replace the glass, then you should be able to find a rub on film with a traditional pattern.

If the window is not in a wet area (like inside the shower) then you could use roman shade with a fabric...........