if they changed the workflow to be like Photoshop, it would leave those of us who know how to use Gimp but not Photoshop high and dry

That's a VERY good point. I think a good example would be how Blender has evolved in the last decade or so.

It started out very "in-house" and unconventional, but it had very specific UX principles in mind rather than just aping "ThE iNdUsTrY". Coming from learning 3D MAX to OG pre-3.5 Blender was really difficult. Right-click select?!

But like Blender, I feel like GIMP could benefit from having easily adjustable settings that could line up with what a particular user finds intuitive. Certain layer behavior seems to be the big one here. The settings are there, they're just awkwardly small buttons or buried in menus.

(Adding the universal transform tool was a VERY nice jump in the right direction.)

Blender's UI / UX overhaul caused a bit of screeching, but overall was instrumental in balancing accessibility with familiarity to existing users. It made those options very accessible and modular.

For instance, I always use left-click-select, but I use the "Blender way" for everything else. If someone's coming from Maya? There's the "industry standard keymap" for them.

Sorry for the ramble. LOL