Keep the end-user's specified (paginated) report parameters as a bookmark
Given the mentioned 'report parameters' functionality in Christopher Finlan last blog (https://powerbi.microsoft.com/en-us/blog/report-parameter-support-for-paginated-report-e-mail-subscriptions-are-now-available/):
"..it should be possible in the next couple of weeks that the end user is being directed back to the view of the report with parameter values set from the link in your mail.."
Given this proposed functionality I think it would also be possible to save the end-user's specified (paginated) report parameters as some-kind of a bookmark. The end-user should be able to maintain multiple 'report parameters' bookmarks and use one of them by default at the start of the report.