What should I do about backgrounds?

The current set of Backgrounds features two planets in the "Floor" set. The "Sky" set has a window, a wall, and a street corner. It makes no sense.

I'd like to rationalize these in some way and have them all make sense. But if I go mucking about and change the items, your saved characters will all of a sudden have something totally different in place when you load it, if you used one of the items (like the aforementioned floor planets).

Which would you rather, potentially having strange saved files, or having Background sets that make sense and were grouped sensibly?