Problem:
If a page with RevDel'ed or suppressed edits was later suppressed and then restored, all of the previous deletion statuses will be lost.

Possible solution:
Add a new column named "ar_deleted_old" or "ar_old_deleted" to the archive table. Then, when a page is deleted (not suppressed), both "ar_deleted" and the new column will be filled with what was in "rev_deleted" prior to the deletion. If a page is suppressed, "ar_deleted" will be filled with 15 for all of the page's revisions, while the new column will be filled with what was in "rev_deleted" prior to the suppression.

Then, when restoring a suppressed page with the checkbox for removing restrictions checked, the new column will be used to populate "rev_deleted" for all the restored revisions. If the new column is not populated, then the current behavior (making "rev_deleted" zero) will continue to be followed. Also, the checkbox's text should be changed to "Restore previous restrictions on restored revisions".