Were there actually any real-world use-cases affected by this? Do any of them not deserve to be named and shamed irregardless of this vulnerability?
If it was up to me, I would nuke the cmd custom implementation, leave some helpful compile error messages behind, and direct users to some 3rd party crates to choose from.
Edit: to be clear, there is no "custom implementation" of cmd itself, nor is the problem exclusive to Rust. This is a problem with the Windows cmd itself.