Wouldn't surprise me, ZFS is pretty bad at recovering from metadata corruption.
I've had a ZFS volume get very thoroughly trashed though by bad writes and still been able to recover data from it (back in the foolish days before ZFS-on-Linux when I had OpenSolaris in a VirtualBox VM with real disks, and something happened that randomly nuked blocks all over one of the filesystems. Interestingly: just the one FS. I had a whole bunch and others were untouched).
You might want to recover at least some files from a badly damaged FS if it is your home server with a baby photos, but would you really do that, if it was accounting of your company and not restore from a backup instead?