I'm kind of a fan of this, at least in theory.Metal, Vulkan, Direct3D 12, and Mantle would be grouped together in this section.
I don't know how disruptive it would be to merge the OpenGL and DirectX forums (applying suitable tags to the existing posts) into a "Classic Graphics APIs" forum. Then we could create a "Modern Graphics APIs" forum (albeit with a better name than that, presumably) to handle the all the variations Spiro lists.
I agree with L, and swift. An old and modern rendering boards would make more sense then the current setup imo.