I think the idea of using Zink instead of rewriting OpenGL drivers is a good idea. Semantically it makes sense because Vulkan is much more low level. They really shouldn't be compiling to the same depth. Just like how the android runtime/open JDK is written in c and c++. The performance of Zink has been pretty good, although as mentioned it requires more of the vulkan spec to be implemented before using it. Better to use that time imrpoving the vulkan driver.