The average windows user will benefit greatly in security from the automatic updates, even if one in a million of them will experience their PC's going into infinite reboot cycle due to incompatible update :)
If anything Microsoft doesn't want another XP where people just refuse to update beyond it. Companies (NHS being a prime example) are willing to pay a lot of money just to be supported still on XP
I don't think anyone has a problem with this being the default, because novices need it, but I think people should have the option to turn it off.