Unlock Origin had a neat feature to let you know if a particular source is updated or outdated, with time stamp, number of domains it is blocking.
It will be good feature to have that information in the Settings>Blacklists http://pi.hole/admin/settings.php?tab=blocklists
This will help us in identifying the source files that are not fetched. I recently noticed some sources with githubusercontent are denied to fetch, same with adaway etc., they can be cleaned so that there is less time when update happens, update won’t make an attempt to fetch source that is only going to timeout.
This also helps in visually identifying critical blacklists, in case you are running on a low power machine or older raspberry pi.