It would be useful, for any given software product or device, to be able to view a graph of compliance over time. This allows easy visual identification of both the patch "dwell time", and also cases where updates may not be successfully targeting all installed/vulnerable devices.
Defender Vulnerability Management does a good job of displaying this as a grid cell just showing the shape of remediation over the past 90 days or so - this alone would be useful, but I'm often frustrated by a lack of ability to determine the date of change, or correlation of when the patch was made available / required to devices.
This feature would assist in evaluating the effectiveness of patch management in general, and also in identifying technical gaps or weaknesses.