Metal wont save the osx client. Granted if they really wanted they could in theory use metal for open gl to dx calls bypassing opengl. In theory. But sense the metal api uses different contexts to do the same functions while its possible to do a metal to dx to metal translation there really is like 0 room for error. Not everything may be supported. May not even work. Problem with that way is the shear amount of development time to write Metal to dx translation layer could more expensive then just writing the native client.
