They already bring the system down for patches, and brought it down again as soon as the severity of the issue was clear. This isn't Guild Wars 2 trying to run dynamic patching w/o making people even log out of the game. And restoring from a pre-release backup explicitly addresses any schema changes that happened w/the release. You go back to the data architecture exactly as it was before you pushed the button. There's nothing wrong w/trying a limited fix forward before committing to a rollback. I think everybody does that to some degree. Nobody wants to redo a release completely if they can avoid it, particularly not over something that could be fixed in 30 minutes. But 9 hours of downtime is WELL beyond any acceptable limit for a 'quick fix.'