I never had a breaking update on Raspbian. However, I have run into write errors caused by power failures that required an fsck on the SD from a different computer: I now have a `@reboot touch /forcefsck` cronjob, but it may just be a talisman (IIRC, dirty filesystems get a fsck automatic at boot)

Have you considered read-only boot & system partitions? That way, your pi will always boot, at the cost of have to remount in read/write mode to perform updates.