If I was to write a tool for recovering zfs volumes, I don't think Windows would be my operating system of choice.
The number of computers that boot up to windows and contain zfs volumes is remarkably small. I actually have such a system - Hyper-V host, drives directly assigned to a FreeBSD virtual machine, but I don't think that's a common setup.
The number of computers that have corrupted disk volumes and are unable to boot up to anything at all is remarkably large; so usually these tools come on a bootable USB stick or similar. Distributing Windows in such a form would be a challenge from a licencing point of view, and Windows on a USB device is not a great experience.