Hi Patrick
I think what you're looking for is Baselines, specifically static baselines. You can create a Baseline for a ditamap on the Manage tab in the AEM Web Editor and AEM will record every map/topic/image/resource referenced and its version.
Add the Baseline to the Output Preset(s) and generate your output. You can be confident that the Baseline contains all the information about the objects used in that publication. You can export the Baseline information to a CSV file.
Later, when you want to re-publish that map and much of its content may have changed, simply take another Baseline. You can compare the Baselines in Excel. Or you can export the DITA for both Baselines and use a tool such as DeltaXML to do a compare.
Once you know which topics have changed, you can review their change history in the Assets UI, in a Review Task or in the AEM Web Editor.
The other really neat thing about Baselines is the ability to correct older content, but be confident that nothing else has changed. If I created a Baseline for a map six months ago and need to make a change to one topic. All I need to do is edit the topic (I can edit the version that was used in that publication by branching it) and then edit the Baseline to use the modified version of the topic. Then republish using the Baseline.
Regards
Keith