Usage details could be so much more powerful if you could filter it in the same way as the timeline. The results of that filter could be turned into a report - without the need to tag.

For example, I tag all my email usage. But there is nowhere to output a spreadsheet grouped by title. Having totals for each group on that table would also be amazing - so you could see instantly that you'd spent 30 mins on one email thread, and 15 minutes on another.