Parity = increased system availability! Meaning you can access your data more of the time without restoring from backup. Parity is never a replacement for backups. Full stop. End of story. Dead horse beaten to a pulp.
A failed resilver on a Z1 system with a proper backup is still a massive PITA. Restoring data from your backups takes time and effort. I am lazy, so therefore I run a Z2 production pool and a z1 backup pool.
As for making your system immune to failure - you will never, ever, ever be able to remove failures completely. Again, backups are required IMHO but I, touch wood, have never had to use them even though I have had a number of HDDs fail in the last 3 years (damn 3TB Seagate shite). Much easier just to swap the caddy and let ZFS do the work. Gah, don't even want to think of the time a full restore would take.
Message of the day: Redundancy will never replace backups. Redundancy can greatly increase system availability.
Bottom line - backup your shite so you don't lose it and pick the parity option that suits your availability needs. If you are happy with restoring from backups from time to time, then use Z1. Personally, I would use Z2 + backup of your choice.
Cheers,