I just upgraded the Installer and found that everyone was locked out because php_LDAP was not enabled. I know that this would have a slight performance hit for people who do not use it, but in the interests of making it easier to get moodle working out of the box, I think it should be enabled, especially as it is one of the standard authentication methods.

The windows installer is already acknowledged as not the best for perfomance and in need of tuning, so disabling LDAP if not needed would be better from the point of view of novice users.