Apparently the single-player option is a reason to not allow pre-downloading patches and creating a character. In PoE we have this feature so that we can login early (an hour before?), create a character and all start right on the release moment. This is a really great feature. In order to make this possible, how about having that patch disable single-player? Once the release has gone well, the next patch can enable single-player again.
People who want to play single player can just not update the game and continue playing the old version for a day.