Currently members of the rollbacker group on the English Wikipedia are limited to 5 rollbacks per minute, presumably to prevent abuse.
Unfortunately, this rate really isn't high enough, and is regularly exceeded while trying to deal with vandalism on the English Wikipedia during busy periods. I could understand such a limit being necessary if rollback was available to all autoconfirmed users, but since it is given out on the English Wikipedia only to individual users at the discretion of administrators, and can be removed again at the first sign of misuse, the potential for abuse seems much lower.
It would be nice if the limit could be raised to a level where it does not interfere with its legitimate use by the group of people which it is intended to benefit. Doubling the limit to 10 edits per minute, or doing away with it altogether, would achieve this.