Should we port existing applications from OpenGL to Vulkan, or should we add an OpenGL abstraction layer on top of Vulkan?
There is currently no existing OpenGL abstraction layer that sits on top of Vulkan. For now, the question should simply be “Should I port my existing application to Vulkan?”
It depends if you want to or if you feel you need to. OpenGL will still continue to be supported on most of the platforms Vulkan is available on. However, if your OpenGL application is CPU limited or bandwidth limited, it might benefit from being ported to Vulkan.