Why is there so little wallpaper and flooring in the game even in the expansions?

I would love to have more options, especially with colors! I want more exterior wall colors so i can have many different color houses. Green is very limited in exterior walls. I would also love more shutter colors. Houses sometimes have shutters with brighter colors (like New Orleans and tropical places). Different hues of colors would be nice as well. I would buy a kit with specific styles of wallpaper (interior/exterior) representing different eras without hesitation!