I like the ability to change the style for the shelves in the library. It would be nice to have a background color selector as well. A quick drop-down next to the style drop-down would be perfect. Having a contrasting background helps especially with the light colored shelves and game box placards.

If you're comfortable using userscripts and liked the retro library, you could install Adalia Fundamentals which has a feature to switch back to that one.