[asoneth]

Now that you mention it, I do know a couple designers who do FOSS development but I doubt they would be interested in doing design or research for someone else's project.

As someone who also jumped from development to design I agree with your description of the friction between developers and designers.

I'll also add that compromise is especially difficult when everyone involved is a volunteer, many of whom seem to be attracted to FOSS partly to reclaim some of the autonomy missing from their day jobs. And when projects become popular many maintainers are petrified of making hard choices that might anger existing users.

Given that, it's not surprising how many FOSS projects fall back to tinkering with icons and colors but otherwise recreate workflows from proprietary competitors.