We occasionally managed to display a decrease in open reports in the
bugzilla weekly reports; I remember we did during at least one annual
hackathon.
Besides, in Phabricator we have no way to tell bugs from feature
requests from random discussions
https://phabricator.wikimedia.org/T102#11218 , nor reports/charts like
https://bugzilla.mozilla.org/reports.cgi?product=Bugzilla&datasets=UNCO…
nor a real advanced search for all task metadata and history.
We could maybe produce dumps of Phabricator data and import them in a
bugzilla instance regularly to ease research, but see
https://phabricator.wikimedia.org/T108199
Nemo