A simple addon for a simple job.
Adding notes to the default ignore list similar to what is possible for friend's list.
Notes are saved per character.
This should allow the user to make a better decision over who to remove from list (light offenders) and who to keep there when needing extra space.
Right-click an entry in the Ignore List and choose Edit Note from the dropdown.
Mouse-over the ignore list to get a tooltip with the ignore note.