Some areas of concern off the top of my head:

• semantic color; if you set the accent color to red, can you still distinguish “dangerous” actions/error states? Same w/green and success, yellow and warning, etc.

• illustrations; they lean on the GNOME palette, will it feel weird that they don’t adapt?

• folder icons; they’re blue, should they adapt, and how?

There are probably more concerns; we last left off with some folks liking some of the proposed solutions to the above, but others not.

Oh, and: how does this interact w/developers using their own accent colors?

The elementary approach (and simplest Adwaita approach) would be that only apps that don’t override the accent color in their app would get the user-chosen accent color, but is that what we/users want?

I believe macOS added a user preference to EITHER have apps use their own accent colors OR to have them use the user-chosen color which adds another layer of complexity I’d want to avoid, but… will users expect that?

Then, there’s known but outstanding work:

• analysis of color use across GNOME/Circle; this is probably the largest outstanding task! Basically, we need to be able to come to the design team with a comprehensive look at how this would affect existing apps and any potentially problematic areas we’d need to proactively address.

• documentation: someone will have to update the Adwaita/GNOME HIG docs with the proper guidance once we know what that even is

• Settings design: how do we expose it?