Simple vandalism
Simple vandalism is easily recognizable by any user and is rarely or never disputed. It is a clearly non-meritorious edit or repeated posting of inappropriate jokes or provably false statements, especially those that seem reasonable (one such posting of a false statement is probably just an error in one's sources, and there might be an accuracy dispute or identity dispute about the issue that goes beyond simple identification and resolution). The most frequent cases are people on a large public wiki who see they can edit this page and decide to erase, not improve, what is there.
Some forms of sysop vandalism are simple as well. For instance, reverting what is clearly an error or spelling or link destination correction, which turns an article from being correct into being wrong, as the edit they reverted made it correct. This commonly occurs where ad hominem revert is tolerated, and the effects of ad hominem delete are not much better - they may for instance lead to an open link not being closed, or even NEVER being closed, if people are intimidated by an inquisitor into not creating ANY article under the same title as the original troll text had specified... in this case vandalism can actually lead to a total breakdown in editing processes.
Much sysop vandalism however is not quite so simple, and, there are many edits on any large public wiki that has any controversial issues at all, that deal with political disputes and real power structures - it is therefore hard to tell any kind of vandalism from troll or simple conflicts between users, especially if one user and not the other is part of the sysop power structure. It is more or less this ability to block IP that defines a troll. Not offering sysops editorial powers nor tolerating ad hominem delete, witch-hunts, etc., is part of what is required to make a troll-friendly wiki where sysop vandalism is uncommon. Or better, unknown.
When everyone involved in a large public wiki notices sysop vandalism, which is INEVITABLE if it is actually simple vandalism that clearly and obviously degrades the quality of the GFDL text corpus, that is a sign that the sysop power structure is so irresponsible that it, and its GodKing, must either change, or lose the best contributors with the highest integrity. This is the highest priority for governance and is one reason to have an independent board - to do mass bans of sysops and start over again...
The next highest priority is to revert simple vandalism quickly and efficiently, and make clear to sysops that this is the only matter they are empowered to deal with without a due process that respects all factions and deals politically with a political dispute, rather than relying on who has the technological power or not. Failing to do so degrades the discourse and is similar to letting those who carry guns, speak, and those who don't carry guns, not. This is certainly the purest form of a w:police state, and it is too high a price to pay simply to revert more than simple vandalism.
It is extremely important not to abuse vandalism in progress as this leads to a casual use of the term "vandalism" and encourages inquisitor and echo chamber problems. Conflicts between users is a better name if it is anything other than simple vandalism that is reverted by more than one sysop. A system that requires sysops to co-operate to do certain things like ad hominem revert or ad hominem delete would be one way to make sure that they saw the issue the same way and agreed on the "reasons why" to do it.