I think everyone is in agreement that the Metal API is pretty nice and there was little objection to making the WebGPU API similar (unless portability concerns dictated otherwise). The main disagreement was over shaders.
Yes, really. There were other reservations about shader compilation in particular from other participants, Apple wasn't alone in that department (e.g. asset sizes and needing to fork the format to maintain compatibility guarantees). They did demand a non-binary format, which sealed the deal on no SPIR-V. But it was not as simple as "SPIR-V/Vulkan was perfect and what everyone except Apple wanted." The shading language by far had the most discussion and iterations; none of the participants in contrast had nearly as many reservations about the structure of the API.
It would be weird if everyone wanted the same thing, Vulkan or otherwise, but it seems quite clear that where Apple wanted something and some others did not, Apple got its way more often than not.
