Currently AbuseFilter uses a default block expiry time defined by the variable $wgAbuseFilterBlockDuration in the configuration file.
It would be good if the settings of the block and its expiry time could be configured locally for each filter when creating one (or modifying it) so we could use different block settings for different filters rather than only one expiry time/settings for all of them.
Also, other block parameters (such as whether the user is blocked form editing their own talk page, etc.) should be set per filter.