My question could be rephrased as: there is a need to put colours in the board
interface?
If we do, please add a switch to disable it to fall back to my preferred
color settings. I don't want the color scheme for every board I open
from other users to look different.
How much time will you spend looking at someone else's board?
1 to 2 minutes? If it is a KiCad support issue (say bug report), it may be important to
see what they are seeing. When I send a word processing document to somebody, the
expectation is that any elaborate text and titles be colored the same as what I used.
Also remember that if your favorite colors are blue and green, you may want them on your
two busiest layers. The two busiest layers change when you are doing a 2 layer board to a
4 layer board. That global color scheme you have will not suffice for all boards. And if
you change it for the 4 layer board, then later load the 2 layer board, you will be
disappointed and have to change it again back. Still don't believe this? Then expand the
example to an 8 layer board and a 2 layer board.
So the question we must ask before proceeding with color storage design is, which is needed?
1) colors are stored in board, or
2) colors are stored globally, or
3) colors can come from either place, and can be "hot swapped" perhaps.
For me, I insist on having colors in the board. That limits the choices to 1) and 3).
With proper interface design and usage, this is not especially hard.