You can very easily build and serialize/deserialize HCL, JSON, YAML or whatever you can come up with outside Kubernetes from the client-side itself (e.g. kubectl). This has actually nothing to do with Kubernetes itself at all.
Given that we're apparently discussing an entire k8s 2.0 based on HCL that hardly seems like a barrier. You'd have needed to write the HCL tooling to get the 2.0 working anyway.
