I didn't realize NetBSD was playing the catch up game with what other distros have had for some time, like ZFS. That's disappointing.
And ZFS is on a lot more than just FreeBSD, even if it's not official. ZFS started on OpenSolaris, not on FreeBSD. OS X has a port. Then FreeBSD got it's port. Linux has a stable port. And there are NAS OS's shipping with it like FreeNAS, TrueNAS, and a device called ReadyDATA by Netgear that has it.
I was mostly surprised at this: "The good stuff that probably won’t make it to NetBSD 7: Stable ZFS." So you're telling me ZFS isn't considered stable on NetBSD? It seems to be that it's pretty stable on quite a few other platforms, some mentioned above.
In BSD world they're completely separate OSes. Their kernels have evolved differently. They may have similar ancestry. You can't just copy and paste code from one to another and expect it to work.