Sheldon's suggestions:
(1) Flexibility on the part of the administrator (Jimbo). If there are no vandals currently active, the current laissez-faire system works fine. When there's a pest afoot, however, Jimbo should be able to temporarily turn on additional security features, such as giving sysops added powers.
Any solution that depends on Jimbo being present is IMHO flawed. Jimbo is usually logged off on the weekends, for example.
(2) The ability to temporarily restrict contributions from non-registered users.
We already have that - IP blocking. We never had a vandal that could switch IPs faster than we could block them. What would be nice is wildcard support at least for the fourth octet.
(3) The ability to create some kind of registration barrier that will make it harder for vandals to get back in the door immediately by simply registering under a new name.
See my suggestion on wikitech to allow sysops to ban signed in users who have made no contributions older than n days. We should also have account creation per IP throttling.
A real ermegency measure would be to only allow users listed on "Most active Wikipedians" to make edits when emergency mode has been switched on.
We could allow any sysop to turn on this emergency mode. If it is turned on, a message would be prominently displayed on every page. If a sysop abuses this privilege, he is promptly banned.
(4) The ability to push a button that will instantly send one million megavolts coursing through the body of Ed Poor. (Just joking.)
No teasing, please ..
Regards,
Erik