How doable would this be? Been thinking about ways to improve the map awareness situation. I know this may be confusing to look at for some but I think I'd personally love it. It would be tolgleable of course and with a configurable transparency level.
This isn't a modding thing sadly. Units on the opposite side of the planet, don't reach the rendering stage, and rasterizing transparent objects needs special care, because unlike non-transparent objects the order in which they are drawn on the screen is relevant. But ... as far as I know icons are culled in the vertex shader (particle_icon.vs). I'm not sure if icons are sorted in the correct z-order, but someone may want to toy around with that.