Edward-
I see that wik has come back and has already started reverting. Something needs to be done.
The easiest and most effective thing to do is for Jimbo to officially authorize the "three revert rule". More than three reverts on the same page per day and you're out for at least one day -- no need for either mediation or arbitration.
If we make an exemption for vandalism, people will claim that non-vandal edits are vandalism and that they are allowed to revert them. So maybe we should not do this, and instead recommend that in cases of vandalism, the user contact a sysop to a) protect the page, or b) ban the vandal.
Regards,
Erik