Earlier quoted context omitted.
The GNUStep project has already done much of the ObjC framework cloning. I wonder if they're using that. Not sure about Swift frameworks, though.
If what you understand by macOS is how Panther used to be.
That's a bit old for me (I started with Tiger), but I would definitely be all over an option to go back to OS X (where, I felt, the paradigm was that users should be presented with the best possible default experience, but also should be trusted to tinker if they chose to do so) before they started pushing this macOS = iOS integration (where the paradigm should be that users should be protected, even against themselves, from any need or ability to tinker).