I don’t know — even a project as old and complex like Blender manages to dedicate a entire release just to a major UI overhaul (and IMO a very good one).

UI should never be a ”someone xan fix it if they like to” issue. People are incredibly opinionated when it comes to UI changes and doing individual changes without a master plan seems like a good way to waste a lot of time just to end up with a convoluted mess that is inconsistent with itself.

The way Blender tackled is was IMO exceptional: very early on the entire discussion was lead by the community with mockups and serious involvement by all sides before any dev ever had to program a line. When they realized the scope grew bigger they asked sucessfully for donations specifically aimed at the new release.

I feel Gimp could use a concentrated effort like that and I’d certainly be willing to help when it gets going