A couple issues pop to mind. My understanding was that this update took a week(+?) to roll out and may still be in progress. It could take them awhile to even start to roll back. Then if you do roll back what do you do about all the people that have changed their settings in the meantime? They have updated their email addresses, perhaps with different ones, so do those get over-written with the old data in all cases? I'm sure it could be figured out but how timely it would be is questionable... not to mention that FB may still be trying to salvage the bump in use for @Facebook.com they were aiming for in the beginning.
I agree it's not a simple fix. Since they have everything stored, they could act as though the address had never been changed. (Primary email should be most recent non-auto-change. Email should be sent to value of primary email address [without auto-change] as configured when email arrived.)
This mistake/bug/zuck-style enhancement has had a colossal negative impact on many people. If Facebook tries to salvage anything from it then it's even more clearly time to walk away. I am not cheerleading for Facebook at all on this, I just want people's contacts back to normal and their emails delivered to where they want them. I think we agree this is possible, in fairly direct contradiction to the title of this article.
