Unfortunately, this is far easier said than done and it is quite time-consuming to implement.
For instance, we have a graphical user interface toolkit that allows users to set up individual settings on a per-application basis.
But, we also have window skins, which include certain defined colors that do not merely affect window decorations but may also influence how applications look in some cases, that are chosen on a per-screen basis.
So, in theory, it can happen that a user sets up an application to look nice with a black window skin and white or light grey text on dark backgrounds. If this application has its windows moved to a different screen that has a white window skin, it will likely look out of place and might end up having the 'wrong' text color, etc.
It is challenging to combine these different concepts without severely limiting the user configurability. It is something that needs to be considered carefully.
That said, important work has been done already. MorphOS 3.10 introduced "graphics-less icons" that utilize Ambient's central icon storage. Rather than always littering the same bitmap or vector graphics thousands of times on your harddisk, Ambient now just needs a single graphic file. As a very much desired side-effect, this also means that switching between different icon graphics for all / most folders can be as easy as replacing a single file.
