Missing metadata in a single field can usually be searched:
<field_lookup_name>:false eg publisher:false
Get the Quality check Plugin
It has checks (and some fixes) for common metadata issues that will be a big plus in consistently formatted fields.
Another field to review, is
last_modified. This timestamp gets bumped any time the data is dirtied. It is not a 100% as a
to do marker because changing a used value in the Lookup Table, can also touch this marker (The 'jacket' page is now stale)