I am very aware of the huge benefits a node system has over layers. But it’s just not practical for layering images the way you’d do it within most 2D Applications.
But I also agree with you my proposed solution of just using the material editor for texture painting is not a great idea. Mabye adding a new datatype of a layered image, that utilizes the material/compositing nodes backend for blending and stuff might be a better solution.
Also It’d really be beneficial to discuss this somehow in person.
(And trust me I’m also not happy with my own color pallete system atm and my posts are really not meant to be about providing perfect solutions but about discussing possibilities to make blender more usable for the needs of 2D-artists, that often deal with color painting…)