Last edit: 19:02, 14 September 2012
Given that nobody answers... I think that in general setting some $wgRateLimits is certainly a good idea, but what configuration would you propose exactly? Such settings can't be changed too frequently so they can't be too strict but this can make them of little use; on the other hand, the situation is not dramatic so it would be a real pity to damage good users.
For specific vandals, especially if we know IP range and so on, AbuseFilter would surely be more effective, because spam and vandalism on this wiki are coming in waves and different (very easy) patterns (first the 6+6 bots and a few others, then the other userpage spambots, then the Selena Gomez fan, then this guy, in the last few days short bio userpage spammers, ...).