Current state: when you have Enable Expand All/Collapse All turned on in a report, you are only able to see one page of data. Outside of the first 50 entries, there is no way to view any of the other records or to navigate to other pages.
Proposed workflow: regardless of if you have Enable Expand All/Collapse All turned on in a report, you should be able to view all of the data that is pulling in to the report. Add the ability to navigate through all records, not just one page of data.