Despite Linux, llvm and Blender proving that open source can beat closed source, GIMP has failed for a very long time. If Microsoft sold something like GIMP, we've never hear the end of criticisms.
I'm not good enough to fix it, but I hope one day a team of great programmers simply restart from scratch. If they simply copied Affinity's or Photoshop's UI and core functionality, we'd have a winner.