Keeping history of locked and unlocked objects
Locking feature doesn't keep history of who has locked or unlocked specific objects in database. This could become useful when a person unlocks an object locked not by him/her and would help to track historical changes.
It would require very few changes - additional history table,
[SQLSourceControl].[LockObject] and [SQLSourceControl].[UnlockObject] procedures would have to be modified.
Possibly an additional view to see that data in SQL Source Control instead of selecting raw tables.