A bag is to a horn what a frame is to a painting (in my opinion). A bag does not need to be flashy if you have a nice horn to "frame". I have gotten simpler in design as I make more bags. A really fancy horn on a really fancy bag can fight each other visually. Sometimes fancy relief carving gets lots on a really curly piece of maple too.
Nothing wrong with a well-constructed, well-finished, unadorned bag with good architecture. Simple also leaves less chance for the "historically correct police" to complain about something.
God Bless, Marc