Thanks for the response TriAnthony. Our data model has 82 tables and 1,134 fields. Each widget is specific to a particular fact table and it's related dimensions. Therefore, creating an overarching drill-in hierarchy is not feasible for us as it would insinuate that drill-in relationships are relevant to a particular widget, when in fact they would result in "N/A" data leading to customer confusion. If we were able to create and manage drill-in hierarchy templates that could be applied at the widget level for a specific set of fact/dimension tables that would absolutely be beneficial. Otherwise, simply allowing for more than 5 "recent" drill-ins would allow the dashboard builders to pre-select the relevant drill-ins for a given widget.
For now, we are just going to pre-define the 5 we that we can, and add text box notes on further drilling based on relevant, related dimensions.