Most of the extensions are for what are currently pre-production or fringe features, and the WG showed they're not afraid of pulling important (and even not so

Most of the extensions are for what are currently pre-production or fringe features, and the WG showed they're not afraid of pulling important (and even not so important) extensions into minor version releases much faster than OpenGL has put things in core with Vulkan 1.1 (I was glad but honestly surprised that the cross-process resource sharing made the cut). You're definitely right about significant parts of the toolchain being weaker. In particular sorting out how glslang -> Vulkan works in practice is pretty trial-and-error, and if you want to use HLSL it's even more poorly documented. You have to expect to be going through the Vulkan spec (which I will say is much easier than directly using the OpenGL spec). However the Vulkan validation layers are incredible, and leave the equivalents for Metal, DirectX, and especially OpenGL in the dust.