[nullindividual]

NT kernel still gets improvements. Think IoRing (copy of io_uring, but for file reads only) which is a new feature.

I think things like Credential Guard, various virtualization (security-related, not VM-related) are relatively new kernel-integrated features, etc.

Kernel bugs that need to exist because of backwards compat are going to continue to exist since backwards compat is a design goal of Windows.