Some other things:
There currently seems to be a bug in File Browser: I can’t select an image. Yesterday that still was possible. have to open images via cmdline.
As you already changed the pipeline and especially became incompatible to RawTherapee: Could you try to allow duplicating tools? One drawback with RTs Favorites tab is that as soon as you add a tool as favorite it gets removed from its original position. Keeping it in the original position seems to be impossible with current RT code. Also a real duplication (new instance) like in darktable (including masks for each tool) would be awesome.
Local edits: I don’t understand why there needs to be a completely new set of tools, it’s the same with RTs newlocallab branch. What newlocallab IMO does better than art: editing is mask-based, I can use several tools for one mask. In ART each tool can have several masks for different editing on different regions. The problem is that I can’t share masks. I often change toning, contrast, brightness, saturation, local contrast, sharpening, … for one area. I have to draw the mask again and again for each tool.
Darktable allows to reuse already existing masks. I can simply select the mask I drew for “basic adjustments” in “local contrast”. If a mask manager is too much for you a simple “copy mask” and “paste mask” shouldn’t be too hard but usable, at least for now.
Lightroom uses a similar approach as newlocallab with the difference that it uses the whole set of globally available adjusters for local editing. I really like that.
Finally: what did you do to the contrast threshold in sharpening?!? In RT when I load high(er) ISO shots dialing up the threshold to not sharpen background noise masks out all the details of the bird, sharpening only the outline. With ART I finally can mask out all the background noise while keeping in all the detail of the subject for sharpening. No idea how you did that but it is AWESOME!
(can’t show screenshots as the images are on another PC)